Imaging apparatus

ABSTRACT

An imaging apparatus includes a front lens group having a front lens element and a reflector; a rear lens group, the imaging apparatus performing an image-stabilizing operation by driving the front lens element; a support member supporting the reflector; a support mechanism which supports the movable frame to spherically swing about a spherical-swinging center, positioned on an extension of the optical axis of the front lens element extending behind an underside of a reflection surface of the reflector; and a rotation preventer which prevents rotation of the movable frame about the optical axis of the front lens element while allowing the movable frame to spherically swing about the spherical-swinging center. The rotation preventer includes a projection and a projection insertion portion provided on the movable frame and the support member, respectively, or vice versa, and are engaged with each other.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an imaging apparatus equipped with animage-stabilizing (image shake correction/shake reduction) system.

2. Description of the Related Art

In recent years, mobile electronic devices which are designed mainly fortaking still/moving photographic images, such as digital cameras(still-video cameras) and digital camcorders (motion-video cameras), andother mobile electronic devices which are designed to be capable oftaking such photographic images as a subsidiary function, such as mobilephones equipped with a camera and smart devices (smart phones or tabletcomputers, etc.) equipped with a camera, have become widespread, andthere has been a demand to miniaturize the imaging units incorporated inthese types of mobile electronic devices. In order to miniaturize animaging unit, it is known in the art to construct an optical system ofan imaging unit as a bending optical system which reflects (bends) lightrays using a reflection surface of a reflector element such as a prismor a mirror. Using a bending optical system in an imaging unit makes itpossible to achieve a reduction in thickness of the imaging unit,especially in the direction of travel of the incident light emanatingfrom an object to be photographed.

In addition, there also has been a tendency for demand to equip imagingunits with a so-called image-stabilizing (image shake correction/shakereduction) system that is designed to reduce image shake on the imageplane that is caused by vibrations such as hand shake. The followingfour different types of imaging units are known in the art as imagingunits using a bending optical system which are equipped with animage-stabilizing system: a first type (disclosed in Japanese UnexaminedPatent Publication Nos. 2009-86319 and 2008-268700) in which an imagesensor is moved in directions orthogonal to an optical axis to reduceimage shake, a second type (disclosed in Japanese Unexamined PatentPublication No. 2010-128384 and Japanese Patent No. 4,789,655) in whicha lens (image-stabilizing lens/image-stabilizing optical element)disposed behind a reflector element (on the image plane side) that has areflection surface is moved in directions orthogonal to an optical axisto reduce image shake, a third type (disclosed in Japanese UnexaminedPatent Publication Nos. 2007-228005, 2010-204341, 2006-330439, andJapanese Patent No. 4,717,529) in which the angle of a reflector element(a reflection surface thereof) and the angle of a lens adjacent to thereflector element are changed to reduce image shake, and a fourth type(disclosed in Japanese Unexamined Patent Publication Nos. 2006-166202and 2006-259247) in which the entire imaging unit is obliquely moved toreduce image shake.

The applicant of the present invention has proposed an image-stabilizingsystem which only moves a front lens element(s) of a front lens groupalong a plane orthogonal to the optical axis of the front lenselement(s) to reduce image shake in an imaging apparatus which containsa bending optical system, wherein the front lens group includes areflector element and the aforementioned front lens element(s) that ispositioned on the object side of the reflector element, and the frontlens group is disposed on the object side in the entire optical systemof the imaging apparatus (disclosed in Japanese Unexamined PatentPublication No. 2013-238848).

In Japanese Unexamined Patent Publication No. H09-251127, in a lenssystem having a straight optical axis, not a bending optical system, itis disclosed that the first lens element, which is positioned closest tothe object side, or the second lens element, which is subsequentlypositioned behind the first lens element, is rotated (swung) about arotational center on an optical axis to perform an image-stabilizingoperation

Bearing in mind that, in addition to still image photography, movingimage photography is now commonly used in imaging apparatuses, there hasbeen a need for further improvement in the image-stabilizing capabilityin imaging apparatuses. However, movements of an optical element toreduce image shake (image-stabilizing optical element) exert an adverseinfluence on the optical performance such as aberrations, and a spacecorresponding to the moving amount of the optical element is required.Accordingly, when attempts are made to improve the image-stabilizingcapability, consideration is required to prevent, as much as possible,these conditions (namely, further miniaturization of theimage-stabilizing system and minimalization of any reduction in theoptical performance due to the image-stabilizing operation) from beingimpaired.

In the first type of image-stabilizing system, a substrate which isconnected to the image sensor moves while following the image sensor;accordingly, the peripheral electrical components, in addition to theimage sensor, need to be designed so as to be compatible with suchmovements, so that the image-stabilizing system tends to be complicatedin structure and high in production cost. In addition, although theperiphery of the imaging surface of the image sensor needs to have adust-resistant structure, it is difficult to secure a sufficient spacewhich allows the image sensor to perform an image-stabilizing operationwhile maintaining a dust-resistant structure within a small imaging unitintended to be incorporated in a cellular phone or a smart device.

In the second type of image-stabilizing system, the moving direction ofthe image-stabilizing lens during an image-stabilizing operationcorresponds to the thickness direction of the imaging unit (theforward/rearward direction with the direction toward an object to bephotographed set to correspond to the forward direction), so that aproblem occurs with it being difficult to incorporate theimage-stabilizing system into the thin imaging unit because the internalspace thereof is limited. Conversely, if this type of image-stabilizingsystem is used, reduction in thickness of the imaging unit becomeslimited. A similar problem exists in the type of image-stabilizingsystem which moves an image sensor, not a lens element, in the thicknessdirection of the imaging unit.

In the third type of image-stabilizing system, a large space is requiredto obliquely move the reflector element and the lens adjacent to thereflector element relative to each other, which easily increases thesize of the imaging unit. In the fourth type of image-stabilizingsystem, in which the entire imaging unit is obliquely moved, theincrease in size of the image-stabilizing system unavoidable.

In the image-stabilizing system disclosed in Japanese Unexamined PatentPublication No. 2013-238848, the effect of miniaturizing (slimming) theimaging apparatus in a direction along the optical axis of the frontlens element is obtained by making the front lens element of the frontlens group, which is positioned in front of the reflector element, movein a plane orthogonal to the optical axis of the front lens element.However, in recent years, it has been desired to achieve, up to a highlevel, both miniaturization and improvement in image-stabilizingperformance of the imaging apparatus equipped with an image-stabilizingsystem.

In the image-stabilizing system disclosed in Japanese Unexamined PatentPublication No. H09-251127, the conceptual rotational centers of thefirst lens element and the second lens element are set on an opticalaxis (optical path); however, to achieve this optical configuration, itis required to arrange the rotational supporters for the first lenselement and the second lens element at positions deviating from theoptical path so as not to cut off light rays traveling in the opticalpath, which makes it difficult to achieve a small and compact design ofthe image-stabilizing system.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides an imaging apparatusequipped with an image-stabilizing system which is small in size andsuperior in image-stabilizing capability.

According to an aspect of the preset invention, an imaging apparatus isprovided, including a front lens group which constitutes part of animaging optical system of the imaging apparatus and includes at leastone front lens element and a reflector, in that order from an objectside, wherein the reflector includes a reflection surface which reflectslight rays, exiting from the front lens element, toward a differentdirection, and wherein the imaging apparatus performs animage-stabilizing operation by driving the front lens element inresponse to vibrations applied to the imaging optical system in order toreduce image shake on the image plane; at least one rear lens groupwhich constitutes another part of the imaging optical system and ispositioned closer to an image plane than the front lens group; a movableframe which holds the front lens element; a support member whichsupports at least the reflector and is immovable relative to an opticalaxis of the front lens element in a reference state in which the imagingapparatus does not drive the front lens element when theimage-stabilizing operation is not performed; a support mechanism whichsupports the movable frame in a manner to allow the movable frame tospherically swing along an imaginary spherical surface about aspherical-swinging center which is positioned on an extension of theoptical axis, of the front lens element, extending behind an undersideof the reflection surface of the reflector; and a rotation preventerwhich prevents rotation of the movable frame about the optical axis ofthe front lens element relative to the support member in the referencestate and a state where the movable frame spherically swings about thespherical-swinging center, while allowing the movable frame tospherically swing about the spherical-swinging center relative to thesupport member, the rotation preventer including a projection and aprojection insertion portion which are provided on one and the other ofthe movable frame and the support member and engaged with each other.

It is desirable for the projection to be slidable relative to theprojection insertion portion along a first plane which includes theoptical axis of the front lens element in the reference state. Withrespect to movement of the projection within a second plane which isorthogonal to the first plane and parallel to the optical axis of thefront lens element in the reference state, the projection is swingablerelative to the projection insertion portion about a point of supportwhich lies in the second plane and movable relative to the projectioninsertion portion in a direction along the optical axis of the frontlens element in the reference state, and is prevented from movingrelative to the projection insertion portion in a direction orthogonalto the optical axis of the front lens element in the reference state.

It is desirable for the first plane to include the optical axis of thefront lens element in the reference state and an optical axis of lightrays reflected by the reflector.

It is desirable for the projection insertion portion to include a pairof holding portions which face each other, on either sides of the firstplane, and hold the projection in the second plane. For example, it isdesirable for the pair of holding portions to include a pair of facingsurfaces which are parallel to the first plane, and for the projectionto include a nonplanar contacting surface which is in sliding contactwith the pair of facing surfaces. Additionally, it is desirable for theprojection insertion portion to include an elongated hole which isformed such that a distance between a pair of end portions of theelongated hole is greater than a distance between the pair of facingsurfaces. The spherical-swinging center is positioned on an extension ofthe elongated hole in the lengthwise direction thereof.

In an embodiment, the projection includes a guide shaft, an axis ofwhich extending along the first plane, and the pair of holding portionsincludes a pair of facing protrusions which hold a portion of the guideshaft in the axial direction thereof. In this case, it is desirable forthe spherical-swinging center to be positioned on an extension of theaxis of the guide shaft.

It is desirable for the projection and the projection insertion portionto come in contact with each other in a plane which passes through thespherical-swinging center and is orthogonal to the optical axis of thefront lens element in the reference state.

It is desirable for the imaging apparatus to include two actuators whichmake the movable frame spherically swing about the spherical-swingingcenter. A first thrust acting plane, which passes through a center of anouter profile of one of the two actuators and includes a thrust actingdirection of the one actuator, and a second thrust acting plane, whichpasses through a center of an outer profile of the other of the twoactuators and includes a thrust acting direction of the other actuator,are each parallel to the optical axis of the front lens element in thereference state, intersect each other at the spherical-swinging centerand are plane-symmetrical with respect to a plane of symmetry whichpasses through a point of the intersection of the first thrust actingplane and the second thrust acting plane and is parallel to the opticalaxis of the front lens element in the reference state.

In an embodiment, the projection and the projection insertion portionare positioned in the plane of symmetry, to which the first thrustacting plane and the second thrust acting plane are plane-symmetrical.

In another embodiment, the projection and the projection insertionportion are positioned in a plane that is orthogonal to the plane ofsymmetry, to which the first thrust acting plane and the second thrustacting plane are plane-symmetrical.

In another embodiment, the projection and the projection insertionportion are positioned in one of the first thrust acting plane and thesecond thrust acting plane.

The first thrust acting plane and the second first thrust acting planecan be orthogonal to each other.

It is desirable for the movable frame to include the projection and thesupport member comprises the projection insertion portion.

According to the present invention, an imaging apparatus equipped withan image-stabilizing system which is slim in the forward/rearwarddirection (with the direction toward an object to be photographed set tocorrespond to the forward direction) and superior in image-stabilizingcapability is obtained due to the structure in which the front lenselement, which is an element of the front lens group that constitutes abending optical system and positioned in front of the reflector element,is made to spherically swing about the spherical-swinging center toperform an image-stabilizing operation. Since the center of thespherical motion is set at a position on an extension of the opticalaxis, of the front lens element, which extends away from the back sideof a reflection surface of the reflector element, the support mechanismfor the movable frame that holds the front lens element can beconstructed in a space-efficient manner. In addition, since the imagingapparatus is provided with the rotation preventer that prevents rotationof the movable frame about the optical axis of the front lens elementrelative to the support member, it is possible to perform the sphericalswinging operation with high precision and stability using alight-weight and simple driver. Hence, an imaging apparatus equippedwith an image-stabilizing system which is small in size and superior inimage-stabilizing capability is obtained.

The present disclosure relates to subject matter contained in JapanesePatent Application Nos. 2014-15885 (filed on Jan. 30, 2014) and2014-57448 (filed on Mar. 20, 2014) which are expressly incorporatedherein by reference in their entireties.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be described below in detail with referenceto the accompanying drawings in which:

FIG. 1 is a perspective view of an imaging unit (imaging apparatus),which includes a first embodiment of a rotation preventer, according tothe present invention;

FIG. 2 is a perspective cut view of the imaging unit shown in FIG. 1,cut along a plane including the first optical axis, the second opticalaxis and the third optical axis of the imaging optical system providedin the imaging unit;

FIG. 3 is a perspective view of the imaging unit with the housingremoved, illustrating the internal structure thereof;

FIG. 4 is a perspective cut view of the internal structure of theimaging unit shown in FIG. 3, cut along a plane including the firstoptical axis, the second optical axis and the third optical axis;

FIG. 5 is an exploded perspective view of the imaging unit, illustratinga state where a body module and a first lens-group unit, which arecomponents of the imaging unit, are separated from each other;

FIG. 6 is an exploded perspective cut view of the imaging unit shown inFIG. 5, illustrating a state where the body module and the firstlens-group unit are separated from each other and cut along a planeincluding the first optical axis, the second optical axis and the thirdoptical axis;

FIG. 7 is a transverse sectional view of the imaging unit, taken along aplane including the first optical axis, the second optical axis and thethird optical axis;

FIG. 8 is an exploded perspective view of the first lens-group unit ofthe imaging unit;

FIG. 9 is a perspective view of a sensor holder shown in FIG. 8 thatconstitutes an element of the first lens-group unit;

FIG. 10 is a front elevational view of the sensor holder, viewed fromthe object side;

FIG. 11 is a perspective sectional view of part of a support mechanismfor the first lens element of the first lens-group unit, taken along aplane including the first optical axis and the second optical axis;

FIG. 12 is a front elevational view of the first lens-group unit, viewedfrom the object side;

FIG. 13 is a sectional view of the first lens-group unit, taken alongthe line XIII-XIII or XIII′-XIII′ shown in FIG. 12;

FIG. 14 is a sectional view of the first lens-group unit, taken alongthe line XIV-XIV shown in FIG. 12;

FIG. 15 is a sectional view of the first lens-group unit, taken alongthe line XIV-XIV shown in FIG. 12 in a state where the first lens framehas been made to swing about the spherical-swinging center of the firstlens frame;

FIG. 16 is a sectional view of the first lens-group unit, taken alongthe line XVI-XVI shown in FIG. 12;

FIG. 17 is a sectional view of the first lens-group unit, taken alongthe line XVI-XVI shown in FIG. 12 in a state where the first lens framehas been made to swing about the spherical swinging center;

FIG. 18 is a sectional view of the first lens-group unit, taken alongthe line XVI-XVI shown in FIG. 12 in a state where the first lens framehas been made to swing about the spherical swinging center in theopposite direction from the direction in the case of FIG. 17;

FIG. 19 is a schematic diagram illustrating a first example of theimaging optical system of the imaging unit, wherein an upper half ofFIG. 19 shows the imaging optical system at the wide-angle extremity anda lower half of FIG. 19 shows the imaging optical system at thetelephoto extremity;

FIG. 20 is a schematic diagram illustrating a second example of theimaging optical system of the imaging unit, wherein an upper half ofFIG. 20 shows the imaging optical system at the wide-angle extremity anda lower half of FIG. 20 shows the imaging optical system at thetelephoto extremity;

FIG. 21 is a schematic diagram illustrating a third example of theimaging optical system of the imaging unit, wherein an upper half ofFIG. 21 shows the imaging optical system at the wide-angle extremity anda lower half of FIG. 21 shows the imaging optical system at thetelephoto extremity;

FIG. 22 is a view similar to that of FIG. 12, showing the firstlens-group unit with the coils removed;

FIG. 23 is a sectional view taken along the line XIII-XIII orXIII′-XIII′ shown in FIG. 12, showing the relationship between the firstlens element, the first prism and an electromagnetic actuator;

FIG. 24A is a perspective view of a pivot guide provided as a member ofthe first embodiment of a rotation preventer, for limiting rotation ofthe first lens frame;

FIG. 24B is a side elevational view of the pivot guide shown in FIG.24A;

FIG. 25A is a perspective view of the pivot guide provided as a memberof a second embodiment of the rotation preventer;

FIG. 25B is a side elevational view of the pivot guide shown in FIG.25A;

FIG. 26A is a perspective view of the pivot guide provided as a memberof a third embodiment of the rotation preventer;

FIG. 26B is a side elevational view of the pivot guide shown in FIG.26A;

FIG. 26C is another side elevational view of the pivot guide shown inFIG. 26A viewed from a direction that is orthogonal to the view of FIG.26B;

FIG. 27A is a perspective view of the pivot guide provided as a memberof a fourth embodiment of the rotation preventer;

FIG. 27B is a side elevational view of the pivot guide shown in FIG.27A;

FIG. 27C is another side elevational view of the pivot guide shown inFIG. 27A viewed from a direction that is orthogonal to the view of FIG.27B;

FIG. 28A is a perspective view of the pivot guide provided as a memberof a fifth embodiment of the rotation preventer;

FIG. 28B is a side elevational view of the pivot guide shown in FIG.28A;

FIG. 28C is another side elevational view of the pivot guide shown inFIG. 28A viewed from a direction that is orthogonal to the view of FIG.28B;

FIG. 29 is a sectional view of the first lens-group unit, taken along aplane including the first optical axis and the second optical axis,which incorporates a sixth embodiment of the rotation preventer, inwhich a guide projection is formed integral with the first lens frame;

FIG. 30 is a sectional view of the first lens-group unit show in FIG.29, taken along a plane orthogonal to the second optical axis;

FIG. 31 is a perspective view of the support mechanism for the firstlens element which is equipped with a seventh embodiment of the rotationpreventer that uses a guide shaft as a rotation limit projection;

FIG. 32 is a rear elevational view of the support mechanism shown inFIG. 31, viewed from the opposite side to the object side;

FIG. 33 is a side elevational view of the support mechanism shown inFIG. 31, viewed from the opposite side to the side on which the secondoptical axis extends;

FIG. 34 is a sectional view of the support mechanism shown in FIG. 31,taken along the line XXXIV-XXXIV shown in FIG. 33;

FIG. 35 is a sectional view of the first lens-group unit, taken along aplane including the first optical axis and the second optical axis,which incorporates an eighth embodiment of the rotation preventer, inwhich the point of contact between a pivot guide and a rotationprevention hole, which are provided as members of the eighth embodimentof the rotation preventer, has been shifted forward;

FIG. 36 is a sectional view of the support mechanism, viewed from theopposite side of the support mechanism from the side on which the secondoptical axis extends, for the first lens element which is equipped witha ninth embodiment of the rotation preventer, in which the point ofcontact between a guide shaft and a rotation prevention hole which areprovided as members of the ninth embodiment of the rotation preventerhas been shifted forward;

FIG. 37 is a sectional view of the support mechanism shown in FIG. 36,taken along the line XXXVII-XXXVII shown in FIG. 36;

FIG. 38 is a perspective view of the support mechanism for the firstlens element which is equipped with a tenth embodiment of the rotationpreventer, in which the arrangement thereof in a plane orthogonal to thefirst optical axis is different from that of the first embodiment of therotation preventer;

FIG. 39 is a perspective view of the support mechanism shown in FIG. 38,viewed from the opposite side to the object side;

FIG. 40 is a front elevational view of the support mechanism shown inFIG. 38, viewed from the object side;

FIG. 41 is a rear elevational view of the support mechanism shown inFIG. 38, viewed from the opposite side thereof from the object side;

FIG. 42 is a sectional view of the support mechanism shown in FIG. 38,taken along the line XLII-XLII shown in FIG. 40;

FIG. 43 is a sectional view of the support mechanism shown in FIG. 38,taken along the line XLIII-XLIII shown in FIG. 41;

FIG. 44 is a perspective view of the support mechanism for the firstlens element which is equipped with an eleventh embodiment of therotation preventer, in which the arrangement thereof in a planeorthogonal to the first optical axis is different from that of the firstembodiment of the rotation preventer;

FIG. 45 is a perspective view of the support mechanism shown in FIG. 44,viewed from the opposite side to the object side;

FIG. 46 is a front elevational view of the support mechanism shown inFIG. 44, viewed from the object side;

FIG. 47 is a rear elevational view of the support mechanism shown inFIG. 44, viewed from the opposite side to the object side;

FIG. 48 is a sectional view of the support mechanism shown in FIG. 44,taken along the line XLVIII-XLVIII shown in FIG. 46; and

FIG. 49 is a sectional view of the support mechanism shown in FIG. 44,taken along the line XLIX-XLIX shown in FIG. 46.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of an imaging unit (imaging apparatus) 10 according to thepresent invention will be discussed below with reference to FIGS. 1through 21. In the following descriptions, forward and rearwarddirections, leftward and rightward directions, and upward and downwarddirections are determined with reference to the directions of thedouble-headed arrows shown in the drawings. The object side correspondsto the front side. As shown by the outward appearance of the imagingunit 10 in FIG. 1, the imaging unit 10 has a laterally elongated shapewhich is slim in the forward/rearward direction and elongated in theleftward/rightward direction.

As shown in FIGS. 2, 4, 6 and 7, an imaging optical system of theimaging unit 10 is provided with a first lens group (front lens group)G1, a second lens group (rear lens group) G2, a third lens group (rearlens group) G3 and a fourth lens group (rear lens group) G4. The firstlens group G1 is provided with a first prism (reflector element) L11,and the imaging unit 10 is provided, on the right-hand side (image planeside) of the fourth lens group G4, with a second prism L12. The imagingoptical system of the imaging unit 10 is configured as a bending opticalsystem which reflects (bends) light rays at substantially right anglesat each of the first prism L11 and the second prism L12. As shown inFIGS. 2, 4, 6 through 8, 13 and 16 through 18, the first lens group G1is configured of a first lens element (at least one front lens elementof the front lens group) L1, the first prism L11 and a second lenselement L2. The first lens element L1 is positioned in front of (on theobject side of) an incident surface L11-a of the first prism L11, whilethe second lens element L2 is positioned on the right-hand side (imageplane side) of an exit surface L11-b of the first prism L11. In theillustrated embodiments, the first lens element L1 is a single lenselement which is disposed so that an incident surface L1-a thereof facestoward the object side and so that an exit surface L1-b thereof facestoward the incident surface L11-a of the first prism L11. Each of thesecond lens group G2, the third lens group G3 and the fourth lens groupG4 is a lens group including no reflector element such as a prism.

As shown in FIG. 7, light rays emanated from the photographic object andincident on the first lens element L1 along a first optical axis O1extending in the rearward direction from the front of the imaging unit10 enter the first prism L11 through the incident surface L11-a and arereflected by a reflection surface L11-c of the first prism L11 in adirection along a second optical axis O2 (extending from left to right)to exit from the exit surface L11-b of the first prism L11.Subsequently, the light rays exiting from the exit surface L11-b passthrough the second lens element L2 of the first lens group G1 and thesecond through fourth lens groups G2, G3 and G4, which lie on the secondoptical axis O2, and are incident on the second prism L12 through anincident surface L12-a thereof. Subsequently, the light rays which arepassed through the incident surface L12-a are reflected by a reflectionsurface L12-c of the second prism L12 in a direction along a thirdoptical axis O3 (extending forwardly) and are incident on the imagingsurface of an image sensor (image pickup device) 14 to form an objectimage thereon. The first optical axis O1 and the third optical axis O3are substantially parallel to each other and lie, together with thesecond optical axis O2, on a common plane. The imaging unit 10 has ashape elongated in a direction along the second optical axis O2, and thefirst lens group G1 is positioned in the vicinity of an end (the leftend) of the imaging unit 10 in the lengthwise direction thereof.

An imaginary plane on which the first optical axis O1, the secondoptical axis O2 and the third optical axis O3 lie is represented by areference plane (first reference plane) P1 (see FIGS. 10, 12, 14 and15). An imaginary plane which is orthogonal to the first reference planeP1 and on which the first optical axis O1 lies is represented by areference plane (second reference plane) P2 (see FIGS. 7, 10, 12 and 16through 18). In addition, when four quadrants V1, V2, V3 and V4, dividedfrom each other by the first reference plane P1 and the second referenceplane P2, are determined with respect to a front view as shown in FIG.12, the first quadrant V1 and the fourth quadrant V4 are positioned onthe side of the second reference plane P2 (the right side of the secondreference plane P2) toward the light-ray traveling direction along thesecond optical axis O2 upon the light rays being reflected by the firstprism L11, while the second quadrant V2 and the third quadrant V3 arepositioned on the opposite side (the left side of the second referenceplane P2) of the second reference plane P2 from the first quadrant V1and the fourth quadrant V4.

As shown in FIGS. 5 and 6, the imaging unit 10 is provided with a bodymodule 11 which holds the second lens group G2, the third lens group G3,the fourth lens group G4, the second prism L12 and the image sensor(image pickup device) 14, and a first lens-group unit 12 which holds thefirst lens group G1. The body module 11 is provided with a box-shapedhousing 13 which is elongated in the leftward/rightward direction andhas a small thickness (slim) in the forward/rearward direction. Thefirst lens-group unit 12 is fixed to one end (the left end), withrespect to the lengthwise direction, of the housing 13, and the fourthlens group G4 and the second prism L12 are fixedly held at the other end(the right end), with respect to the lengthwise direction, of thehousing 13. The image sensor 14, which is positioned immediately infront of the second prism L12, is fixedly mounted to an image sensorsubstrate 15 which is fixed to the housing 13.

As shown in FIGS. 3 and 4, the second lens group G2 and the third lensgroup G3 are held by a second lens group frame 20 and a third lens groupframe 21, respectively, which are supported to be movable along thesecond optical axis O2 by a pair of rods 22 and 23 provided in thehousing 13. The imaging unit 10 is provided with a first motor M1 (seeFIGS. 1, 3 and 5) and a second motor M2 (see FIG. 4) that are supportedby the housing 13. When the first motor M1 is driven to rotate a screwshaft M1 a thereof which projects from the body of the first motor M1,this rotation is transmitted to the second lens group frame 20 to movethe second lens group frame 20 along the pair of rods 22 and 23. Whenthe second motor M2 is driven to rotate a screw shaft M2 a thereof whichprojects from the body of the second motor M2, this rotation istransmitted to the third lens group frame 21 to move the third lensgroup frame 21 along the pair of rods 22 and 23. The imaging opticalsystem of the imaging unit 10 is a zoom lens system (variable-focallength lens system), and a zooming operation (power-varying operation)is performed by moving the second lens group G2 and the third lens groupG3 along the second optical axis O2. In addition, a focusing operationis performed by moving the third lens group G3 along the second opticalaxis O2.

The imaging unit 10 is provided with an image-stabilizing (image shakecorrection/shake reduction) system that reduces image shake on an imageplane which is caused by vibrations such as hand shake. Thisimage-stabilizing system causes the first lens element L1 of the firstlens group G1 to spherically swing along an imaginary spherical surfaceabout a spherical-swinging center A1 (see FIGS. 13 and 16 through 18)which is positioned on a straight line extended from the first opticalaxis O1. This swinging operation of the first lens element L1 along theimaginary spherical surface about the spherical-swinging center A1 willbe hereinafter referred to as the spherical swinging operation. Thefirst optical axis O1 in the drawings of the present embodiment denotesthe position of the first optical axis O1 in a state where the firstlens element L1 is positioned at an initial optical-design position ofthe first lens element L1 when no image shake correction operation isperformed (i.e., at the center of the driving range thereof in thespherical swinging operation by the image-stabilizing system). Thisstate will be hereinafter referred to as the image-stabilizing initialstate. The optical axis of the first lens element L1 in a state wherethe spherical swinging operation has been performed from theimage-stabilizing initial state is designated by O1′ in FIGS. 15, 17 and18. Additionally, a third reference plane P3 which passes through thespherical-swinging center A1 and is orthogonal to the first optical axisO1 is shown in FIGS. 13 through 18 and 23.

The incident surface L1-a and the exit surface L1-b of the first lenselement L1 face toward the object side and the first prism L11,respectively, and the first lens element L1 has a D-cut shape that isformed (defined) with a portion of the outer edge (circular edge withits center on the first optical axis O1) of the first lens element L1which is positioned in the first quadrant V1 and the fourth quadrant V4cut out along a plane extending in the upward/downward direction (i.e.,the edge of the cut-out portion appears as a straight line that issubstantially orthogonal the second optical axis O2 when viewed from thefront side (from the object side)) as shown in FIG. 12. Specificconditions for the shape of the first lens element L1 will be discussedin detail later.

As shown in FIG. 8, the first lens-group unit 12 is provided with afirst lens frame (movable frame) 30 which holds the first lens elementL1, a base member (support member) 31 which holds the first prism L11,and a cover member (support member) 32 which covers the first lens frame30 and the base member 31 from the front. The first lens-group unit 12is further provided with a coil connecting board 33, a sensor holder(support member) 34, a sensor support board 35, a leaf spring 36, asensor fixing plate 37, a second lens frame 38 which holds the secondlens element L2, and a pivot guide 39. In addition, the first lens-groupunit 12 is provided with a pair of permanent magnets 81 and 82 and apair of coils 83 and 84 which constitute an electromagnetic actuator fordriving the first lens frame 30 (the first lens element L1), and isfurther provided with a pair of Hall sensors 85 and 86 for detecting theposition of the first lens frame 30 (the first lens element L1) that iscontrolled by the electromagnetic actuator. In each of FIGS. 13 and 23,the position of a cross section taken along the line XIII-XIII shown inFIG. 12 that passes through the permanent magnet 81 and the coil 83, andthe position of a cross section taken along the line XIII′-XIII′ shownin FIG. 12 that passes through the permanent magnet 82 and the coil 84are shown altogether; furthermore, the elements included in the crosssection along the line XIII′-XIII′ are designated by parenthesizedreference characters to be distinguished from those included in thecross section along the line XIII-XIII. As can be perceived from FIGS.13 and 23 (and upon referring to FIG. 12), these two cross sectionalpositions are substantially symmetrical to the first reference plane P1.

As shown in FIGS. 8, 12, 13, 22 and 23, each of the permanent magnets 81and 82 is in the shape of a flat rectangular cuboid, and the permanentmagnets 81 and 82 are substantially identical in shape and size to eachother. As shown in FIGS. 8, 12, 13, 22 and 23, the coil 83 is anair-core coil which includes a pair of linear portions 83 a that aresubstantially parallel to each other and a pair of curved (U-shaped)portions 83 b which connect the pair of linear portions 83 a at therespective ends thereof. In addition, the coil 83 is a flat coil whichis small in thickness in the direction through the air-core of the coil83 compared with the size of the coil 83 in the lengthwise directionthereof, in which the pair of linear portions 83 a extend, and the sizeof the coil 83 in the widthwise direction thereof, in which the pair oflinear portions 83 a traverse. Likewise, the coil 84 is an air-core coilwhich includes a pair of linear portions 84 a that are substantiallyparallel to each other and a pair of curved (U-shaped) portions 84 bwhich connect the pair of linear portions 84 a at the respective endsthereof. In addition, the coil 84 is a flat coil which is small inthickness in the direction through the air-core of the coil 84 comparedwith the size of the coil 84 in the lengthwise direction thereof, inwhich the pair of linear portions 84 a extend, and the size of the coil84 in the widthwise direction thereof, in which the pair of linearportions 84 a traverse. The coils 83 and 84 are substantially identicalin shape and size to each other.

The first lens frame 30 is provided with a lens holding portion 40, asupport portion 41 and a pair of magnet holding portions 42 and 43. Thelens holding portion 40 is in the shape of a lens frame, and the firstlens element L1 is fixedly fitted into the lens holding portion 40. Thesupport portion 41 extends rearward from the lens holding portion 40,and the pair of magnet holding portions 42 and 43 are connected to theouter periphery of the lens holding portion 40. A portion of the outeredge of the lens holding portion 40 which is positioned in the firstquadrant V1 and the fourth quadrant V4 is cut out along a plane parallelto the second reference plane P2 to be formed into a linear-cut portion40 a to correspond in outer profile of the first lens element L1. Theother portion of the outer edge of the lens holding portion 40 is formedinto a circular frame portion 40 b, so that the lens holding portion 40is in the shape of an imperfect circular frame.

As shown in FIGS. 14 and 15, the support portion 41 of the first lensframe 30 is provided with a pair of leg portions 41 a which are spacedfrom each other in the upward/downward direction (in a circumferentialdirection about the first optical axis O1) and a connecting portion 41 bwhich extends in the upward/downward direction. The pair of leg portions41 a project rearward from the circular frame portion 40 b of the lensholding portion 40, and the rear ends of the pair of leg portions 41 aare connected via the connecting portion 41 b (see FIG. 14). As shown inFIGS. 16 through 18, the pair of leg portions 41 a and the connectingportion 41 b are positioned on the opposite side of the second referenceplane P2 (the left side of the second reference plane P2) from the sideon which the second optical axis O2 extends, and a cantilever pivot arm41 c projects from the connecting portion 41 b in a direction toapproach the second reference plane P2 (the first optical axis O1). Apivot projection (an element of a support mechanism for the movableframe) 44 is formed at the free end of the pivot arm 41 c. As shown inFIGS. 11, 13 and 16 through 18, the pivot projection 44 is conical inshape which tapers in the rearward direction, i.e., reducing in diameterin the rearward direction, and the end of the pivot projection 44 isshaped into a smooth spherical ball (spherical tip).

As shown in FIGS. 24A and 24B, the pivot guide 39 is provided at the end(rear end) of a columnar base 39 a thereof with a spherical guideprojection 39 b and is provided with a flange 39 c, which is greater indiameter than the guide projection (projection as an element of arotation preventer) 39 b, between the base 39 a and the guide projection39 b. As shown in FIGS. 11 and 14 through 18, the base 39 a of the pivotguide 39 is inserted into a hole from behind, which is formed in theconnecting portion 41 b of the support portion 41 of the first lensframe 30, and the flange 39 c is made to contact the connecting portion41 b to thereby define the inserted position of the base 39 a relativeto the connecting portion 41 b (the support portion 41). In this state,the guide projection 39 b projects rearward from the support portion 41.

As shown in FIG. 13, the pair of magnet holding portions 42 and 43 ofthe first lens frame 30 are formed to project obliquely rearward fromthe circular frame portion 40 b to be inclined so that the distance fromthe first optical axis O1 to each of the magnet holding portions 42 and43 increases with respect to a the direction toward the outer ends ofthe magnet holding portions 42 and 43 (i.e., in a direction away fromthe circular frame portion 40 b). In a state where the first lens frame30 is in the image-stabilizing initial state, in which the first lenselement L1 is positioned at the center of the driving range thereof bythe image-stabilizing system (i.e., at an initial optical-designposition of the first lens element L1 when no image shake correctionoperation is performed), the magnet holding portions 42 and 43 arepositioned in the second quadrant V2 and the third quadrant V3 to besubstantially symmetrical with respect to the first reference plane P1.The permanent magnet 81 is fitted into and held by a recess formed inthe magnet holding portion 42, and the permanent magnet 82 is fittedinto and held by a recess formed in the magnet holding portion 43.Accordingly, as shown in FIGS. 12 and 22, the permanent magnet 81 ispositioned in the second quadrant V2 and the permanent magnet 82 ispositioned in the third quadrant V3.

The base member 31 is a frame-like member which is substantiallyrectangular in outer shape as viewed from front. The base member 31 isprovided with a pair of side walls 51 which are spaced from each otherin the upward/downward direction and project rightward from a mountingportion 50, which constitutes the left end portion of the base member31. The base member 31 is further provided with a front bridging portion52, which connects the front sides of the right ends of the pair of sidewalls 51, and a prism holding wall 53 which connects middle portions ofthe pair of side walls 51. As shown in FIGS. 11, 13 and 16 through 18,the prism holding wall 53 has a shape extending along the reflectionsurface L11-c of the first prism L11 and constitutes an inclined wallwhich projects progressively forward in the direction from the right endside of the first lens-group unit 12, on which the second lens elementL2 is positioned, to the left end side of the first lens-group unit 12,on which the mounting portion 50 is provided. As shown in FIGS. 13through 18, in the base member 31, an optical path space 54 is formed infront of the prism holding wall 53, and a rear space 55 is formed behindthe prism holding wall 53. In addition, a side space 56 which iscommunicatively connected with the rear space 55 is formed between themounting portion 50 and the prism holding wall 53. The optical pathspace 54 is open at the front side and the right end side of the basemember 31 with the front bridging portion 52 as a border.

The first prism L11 is fixedly fitted into the optical path space 54 ofthe base member 31. The first prism L11 is provided with the reflectionsurface L11-c which is positioned at an angle of substantially 45degrees with respect to the incident surface L11-a and the exit surfaceL11-b, and a pair of side surfaces L11-d (only one of which is shown inFIG. 8) which are substantially orthogonal to both the incident surfaceL11-a and the exit surface L11-b. The position of the first prism L11 inthe optical path space 54 is defined by the back side (underside) of thereflection surface L11-c being held by the prism holding wall 53 and bythe pair of side surfaces L11-d being sandwiched between the pair ofside walls 51. In this supported state of the first prism L11, theincident surface L11-a is positioned on the first optical axis O1 andfaces forward, and the exit surface L11-b is positioned on the secondoptical axis O2 and faces rightward. Additionally, the second lens frame38 that holds the second lens element L2 is fixedly installed in theoptical path space 54 of the base member 31 to be positioned on theright-hand side of the first prism L11 (behind the front bridgingportion 52).

The base member 31 is provided, in the rear of the prism holding wall53, with a pair of cylindrical support seats 57 (see FIG. 8) which areformed as mounts for the sensor holder 34 at different positions in theupward/downward directions. A screw hole (not shown) which opens at therear is formed in each support seat 57. The base member 31 is furtherprovided at the left end of the prism holding wall 53 with a springsupport 58 which serves as amount to which the leaf spring 36 ismounted.

As shown in FIGS. 13 and 16 through 18, the leaf spring 36 is arrangedbehind and along the prism holding wall 53 of the base member 31. Theleaf spring 36 is provided with a mounting plate 36 a in which athrough-hole is formed and a resilient arm 36 b which is formed into acantilever extending from the mounting plate 36 a. The leaf spring 36 issupported by the base member 31 by fitting the through-hole of themounting plate 36 a onto a projection formed on the spring support 58.In this supported state of the leaf spring 36, the resilient arm 36 bcan be resiliently deformed in the rear space 55 that is formed behindthe prism holding wall 53.

As shown in FIGS. 9 and 10, the sensor holder 34 is provided with abaseplate portion 60, a pair of sensor support projections 61 and 62 and abase plate support projection 63. Each of the pair of sensor supportprojections 61 and 62 is formed on the base plate portion 60 to projectlike an upright wall, and the base plate support projection 63 projectsforward from the base plate portion 60 to be positioned between the pairof sensor support projections 61 and 62. As shown in FIG. 13 that showsthe assembled state of the first lens-group unit 12, the pair of sensorsupport projections 61 and 62 project obliquely forward from the baseplate portion 60 so as to face the magnet holding portions 42 and 43 ofthe first lens frame 30, respectively. A sensor insertion recess 64 isformed in each of the sensor supporting projections 61 and 62. The baseplate support projection 63 is formed as a small (low) projection whichprojects from the base plate portion 60 by a smaller amount ofprojection than the sensor support projections 61 and 62.

The sensor support board 35 is a flexible board and provided with, at anend of a narrow strip portion 35 a thereof, a support sheet portion 35 bhaving the shape of a thin flat plate as shown in FIG. 8. The sensorsupport board 35 is further provided on both sides of the strip portion35 a with a pair of sensor support lugs 35 c and 35 d which are formedso that the support sheet portion 35 b are partly bent and raised. TheHall sensor 85 and the Hall sensor 86 are mounted to and supported bythe sensor support lug 35 c and the sensor support lug 35 d,respectively. The sensor support board 35 is fixed to the sensor holder34 using the sensor fixing plate 37 by making the support sheet portion35 b supported by the base plate support projection 63 (see FIGS. 7, 11and 16 through 18) and by inserting the Hall sensors 85 and 86, whichare respectively mounted on the sensor support lugs 35 c and 35 d, intothe sensor insertion recesses 64, which are formed in the pair of sensorsupport projections 61 and 62 (see FIG. 13). The strip portion 35 a ofthe sensor support board 35 is electrically connected to a controlcircuit (not shown) which controls the operation of the imaging unit 10so that information on the outputs of the Hall sensors 85 and 86 istransmitted to the control circuit via the sensor support board 35.

As shown in FIGS. 9 and 10, the sensor holder 34 is provided on the baseplate portion 60 with a pair of ring-shaped abutting portions 65, a pairof screw insertion holes 66, a pivot recess (a member of the supportstructure for the movable frame) 67 and a rotation prevention hole(projection insertion portion as a member of the rotation preventer) 68.The pair of ring-shaped abutting portions 65 abut against the ends ofthe pair of support seats 57 of the base member 31. The pair of screwinsertion holes 66 are formed at the centers of the pair of ring-shapedabutting portions 65, respectively. The pivot recess 67 and the rotationprevention hole 68 are formed between the pair of abutting portions 65.As shown in FIGS. 9 through 11, 13 and 16 through 18, the pivot recess67 is a recess having a mortar-shaped (conical-shaped) inner surfacewhich allows the pivot projection 44 to fit into, and the innermost baseportion of the pivot recess 67 is formed into a spherical shape whichcorresponds to the end shape (spherical tip) of the pivot projection 44.The rotation prevention hole 68 is an elongated hole which is elongatedin a radial direction of the pivot recess 67 at a position spaced awayfrom the axis of the pivot recess 67, and the rotation prevention hole68 allows the guide projection 39 b of the pivot guide 39 to entertherein, as will be discussed later. The width of the rotationprevention hole 68 corresponds to the diameter of the guide projection39 b, so that the rotation prevention hole 68 does not allow the guideprojection 39 b to move in the widthwise direction of the rotationprevention hole 68 when the guide projection 39 b is in the rotationprevention hole 68. On the other hand, the length of the rotationprevention hole 68 is greater than the diameter of the guide projection39 b, so that the rotation prevention hole 68 allows the guideprojection 39 b to move in the lengthwise direction of the rotationprevention hole 68 when the guide projection 39 b is in the rotationprevention hole 68.

With the sensor support board 35 mounted to the sensor holder 34, thesensor holder 34 is fixed to the base member 31 by inserting the pair ofsensor support projections 61 and 62 into the side space 56 (see FIG.13), making the pair of abutting portions 65 abut against the pair ofsupport seats 57 and screwing two set screws 69 (see FIG. 8) into screwholes formed in the pair of support seats 57 through the screw insertionholes 66 of the pair of abutting portions 65. In this fixed state, thebase plate portion 60 of the sensor holder 34 closes the back of therear space 55 of the base member 31, and the center of the pivot recess67, which is formed on the base plate portion 60, lies on an extensionof the first optical axis O1 (see FIGS. 13 and 16 through 18). Inaddition, the rotation prevention hole 68 is positioned on the left-handside of the pivot recess 67 and elongated along the first referenceplane P1 (see FIGS. 10 and 12).

Upon assembling the first lens-group unit 12, the leaf spring 36 is madeto be supported by the base member 31, subsequently the first lens frame30 is disposed at a predetermined position with respect to the basemember 31, and the sensor holder 34 is fixed to the base member 31. Inthis state, the first lens frame 30 is supported by the base member 31with the pivot arm 41 c inserted into the rear space 55 so that thepivot projection 44 fits into the pivot recess 67 and with the guideprojection 39 b of the pivot guide 39 inserted into the rotationprevention hole 68. As shown in FIGS. 7, 11, 13 and 16 through 18, thepivot arm 41 c which is inserted into the rear space 55 abuts against aportion of the resilient arm 36 b in the vicinity of the free endthereof to resiliently deform the resilient arm 36 b forward; the end ofthe pivot projection 44 is pressed against the bottom of the pivotrecess 67 by the resiliency of the resilient arm 36 b of the leaf spring36. In this supported state of the first lens frame 30, the lens holdingportion 40 is positioned at the front opening of the optical path space54, and the first lens element L1 is positioned in front of the incidentsurface L11-a of the first prism L11. As shown in FIG. 13, the pair ofmagnet holding portions 42 and 43 are inserted into the side space 56 ofthe base member 31 so that the magnet holding portion 42 is positionedadjacent to the sensor support projection 61 of the sensor holder 34 andso that the magnet holding portion 43 is positioned adjacent to thesensor support projection 62 of the sensor holder 34.

The cover member 32 is provided with a pair of side walls 70, a frontportion 71 and a stepped portion 72. The pair of side walls 70 areshaped to be fitted onto the outer sides of the pair of side walls 51′of the base member 31, respectively, the front portion 71 covers thefront of the pair of side walls 70, and the stepped portion 72 is formedat the left end of the front portion 71. The cover member 32 is mountedto the base member 31 by abutting the front portion 71 against the frontof the base member 31 and by engaging projections 51 a which are formedon a side of each side wall 51 of the base member 31 engaging intoengaging holes 70 a which are formed in the associated side wall 70. Aphotographing aperture 75 through which the first lens element L1 isexposed is formed in the front portion 71.

As shown in FIG. 13, two coil holding portions 73 and 74 which are eachshaped into a recess are formed in an inner side of the cover member 32in the vicinity of the boundary between the front portion 71 and thestepped portion 72 of the cover member 32, and the coils 83 and 84 arefitted into and held by the coil holding portions 73 and 74,respectively. Mounting the cover member 32 to the base member 31 causesthe coils 83 and 84 to be positioned to face the permanent magnets 81and 82, respectively. A driving current is passed through the coils 83and 84 via the coil connecting board 33. The coil connecting board 33 isa flexible board, provided with a narrow strip portion 33 a and a coilconnecting portion 33 b. The coil connecting portion 33 b is supportedby the stepped portion 72 and is electrically connected to the coils 83and 84, which are fitted into the coil holding portions 73 and 74.

The first lens-group unit 12 is constructed as described above, and iscombined with the body module 11 as shown in FIGS. 5 and 6. The housing13, which constitutes part of the body module 11, is provided with aunit support portion 13 a, into which the rear of the base member 31 ofthe first lens-group unit 12 is fitted and supported thereby. Thehousing 13 is provided at the left end of the unit support portion 13 awith a screw hole 13 b and a pair of positioning pins 13 c. The mountingportion 50 of the base member 31 is provided with a screw insertion hole50 a which is aligned with the screw hole 13 b, and is further providedwith a pair of positioning holes 50 b into which the pair of positioningpins 13 c are fitted. By supporting the first lens-group unit 12 by theunit support portion 13 a thereon while fitting the pair of positioningpins 13 c into the pair of positioning holes 50 b and by screwing a setscrew 16 into the screw hole 13 b through the screw insertion hole 50 a,the body module 11 and the first lens-group unit 12 are connected tocomplete the assembly of the imaging unit 10.

As described above, in the first lens-group unit 12, the first lensframe 30 is supported by a combination of the base member 31 and thesensor holder 34 (which is fixed with respect to the housing 13) via theengagement between the pivot projection 44 and the pivot recess 67. Thepivot recess 67 is a recess which is open at the front of the base plateportion of the sensor holder 34 and has a mortar-shaped (conical-shaped)inner surface which progressively reduces the diameter thereof in thedirection toward the bottom of the recess, and the innermost baseportion of the pivot recess 67 is formed into a concave spherical shape.This concave spherical surface is a part of a spherical surface aboutthe spherical-swinging center A1. The pivot projection 44 is aprojection having a conical outer surface which progressively reducesthe diameter thereof in the direction toward the end of the pivotprojection 44, and the end of the pivot projection 44 is shaped as aconvex spherical tip. This convex spherical tip is a part of a sphericalsurface that is centered about the spherical-swinging center A1. Theleaf spring 36 provides a force that presses the end of the pivotprojection 44 against the bottom of the pivot recess 67, and the firstlens frame 30 is supported to be capable of spherically swinging aboutthe spherical-swinging center A1 (inclining the pivot projection 44relative to the pivot recess 67) by being guided by the contactingportion between the pivot projection 44 and the pivot recess 67. Sincethe end of the pivot projection 44 is formed as a part of a sphericalsurface about the spherical-swinging center A1, this spherical swingingoperation is performed while changing the point of contact between thepivot projection 44 and the pivot recess 67 without changing theposition of the spherical-swinging center A1. As can be seen from FIGS.11 and 13, the conical inner surface of the pivot recess 67 is formedinto the shape of a circular cone having a greater central angle thanthat of the conical outer surface of the pivot projection 44, therebyallowing the first lens frame 30 to perform the spherical swingingoperation without interference. In addition, since the contactingportion between the pivot projection 44 and the pivot recess 67 formspart of a spherical surface about the spherical-swinging center A1 (theaforementioned convex spherical tip and the aforementioned concavespherical surface), when the first lens frame 30 performs the sphericalswinging operation, the resilient arm 36 b of the leaf spring 36 doesnot move in the forward/rearward direction, so that the spring load ofthe leaf spring 36 does not vary (the resilient arm 36 b gives a fixeddegree of load onto the end of the pivot projection 44 in theforward/rearward direction and prevents no superfluous load fromoccurring in directions other than the forward/rearward direction). Thismakes it possible to achieve a stable image-stabilizing control withhigh precision without the electromagnetic actuator (the permanentmagnets 81 and 82 and the coils 83 and 84) exerting an adverse influenceon the drive control of the first lens frame 30.

As shown in FIGS. 7, 13 and 16 through 18, the spherical-swinging centerA1 lies on an extension of the first optical axis O1 which extends tothe rear of the reflection surface L11-c of the first prism L11, and theexit surface L1-b of the first lens element L1 is a concave surfacewhich faces the spherical-swinging center A1. FIGS. 7, 12, 13 and 14through 16 show the aforementioned image-stabilizing initial state, inwhich the first lens frame 30 (the first lens element L1) is positionedat the center of the driving range thereof in the spherical swingingoperation by the image-stabilizing system, and FIGS. 15, 17 and 18 eachshow a state where the first lens frame 30 (the first lens element L1)has been swung in the spherical swinging operation from theimage-stabilizing initial state. More specifically, FIG. 15 shows astate where the first lens frame 30 has been tilted toward the upperside of the imaging unit 10, FIG. 17 shows a state where the first lensframe 30 has been tilted toward the left side of the imaging unit 10 andFIG. 18 shows a state where the first lens frame 30 has been tiltedtoward the right side of the imaging unit 10.

The pivot guide 39 and the rotation prevention hole 68 serve as arotation preventer which prevents rotation of the first lens frame 30about the optical axis of the first lens element L1 (which includes boththe first optical axis O1 (non-inclined optical axis) of the first lenselement L1 in the image-stabilizing initial state and a first opticalaxis O1′ (inclined optical axis) of the first lens element L1 in a statewhere the spherical swinging operation has been performed from theimage-stabilizing initial state) while allowing the first lens frame 30to perform the spherical swinging operation. In the completed assembledstate of the imaging unit 10, the rotation prevention hole 68 is formedas an elongated hole, which is elongated in a radial direction of animaginary line extended rearward from the first optical axis O1. Morespecifically, as shown in FIGS. 9 through 12 and 14 through 18, therotation prevention hole 68 is provided with a pair of facing surfaces(holding portions) 68 a, which are formed as a pair of parallelsurfaces, and a pair of end portions 68 b which connect the pair offacing surfaces 68 a; and the length of the rotation prevention hole 68,which corresponds to the distance along a central line connecting thepair of end portions 68 b, is greater than the width of the rotationprevention hole 68, which is defined by the distance between the pair offacing surfaces 68 a. The rotation prevention hole 68 is positionedalong the boundary between the second quadrant V2 and the third quadrantV3, and the pair of facing surfaces 68 a are substantially parallel tothe first reference plane P1 and are positioned substantiallysymmetrical to the first reference plane P1. As shown in FIGS. 11 and 16through 18, the rotation prevention hole 68 is formed at a positionsubstantially identical to the position of the pivot recess 67 (i.e., ata position in the third reference plane P3), with respect to theforward/rearward direction of the imaging unit 10. The guide projection39 b of the pivot guide 39 which is inserted into the rotationprevention hole 68 (that is positioned in the aforementioned manner) isa spherical end, the diameter of which is substantially identical to thewidth of the rotation prevention hole 68 (i.e., the distance between thepair of facing surfaces 68 a), and the surface of the spherical end isin contact (point contact) with the pair of facing surfaces 68 a. Whenthe first lens frame 30 is in the image-stabilizing initial state, thecontact point between the guide projection 39 b and each facing surface68 a lies in the third reference plane P3 (see FIGS. 14 and 16). Inaddition, the prevention of movement of the guide projection 39 b in thewidthwise direction of the rotation prevention hole 68 with the guideprojection 39 b held between the pair of facing surfaces 68 a preventsrotation of the first lens frame 30 about the optical axis of the firstlens element L1. When the first lens frame 30 is in theimage-stabilizing initial state, the optical axis of the first lenselement L1 is coincident with the first optical axis O1 shown in thedrawings, and accordingly, the guide projection 39 b and the rotationprevention hole 68 prevent rotation of the first lens frame 30 about thefirst optical axis O1. On the other hand, in a state where the firstlens frame 30 tilts from the position thereof in the image-stabilizinginitial state by the spherical swinging operation, rotation of the firstlens frame 30 about the inclined first optical axis O1′ (see FIGS. 15,17 and 18) is prevented by the guide projection 39 b and the rotationprevention hole 68.

As can be understood from FIG. 12, the rotation prevention hole 68 isgreater in size than the diameter of the guide projection 39 b in thelengthwise direction of the rotation prevention hole 68 (theleftward/rightward direction of the imaging unit 10), in which the pairof end portions 68 b face each other, so that the guide projection 39 bis slidable in the lengthwise direction of the rotation prevention hole68 along the pair of facing surfaces 68 a. In addition, as can beunderstood from FIGS. 11 and 14 through 18, the rotation prevention hole68 has a size allowing the guide projection 39 b to slide also in thedepthwise direction of the rotation prevention hole 68 (theforward/rearward direction of the imaging unit 10). Additionally, theguide projection 39 b, the spherical surface of which is in pointcontact with the pair of facing surfaces 68 a, can swing (tilt) with acenter B1 (see FIGS. 12 and 14 through 18) of the spherical end(hereinafter referred to as the spherical center) of the guideprojection 39 b serving as a swinging center (fulcrum). Accordingly,with respect to a first plane defined as a plane parallel to each facingsurface 68 a and parallel to the first reference plane P1, the guideprojection 39 b can slide relative to the rotation prevention hole 68along this first plane in the forward/rearward direction and theleftward/rightward direction of the imaging unit 10 within the range ofthe area of the pair of facing surfaces 68 a. Additionally, with respectto a second plane defined as a plane which is orthogonal to both eachfacing surface 68 a and the first reference plane P1 and parallel to thefirst optical axis O1 (i.e., a plane parallel to the second referenceplane P2), the guide projection 39 b can slide, within this secondplane, in the forward/rearward direction along the first optical axis O1and swing about the spherical center B1 (see FIG. 15) relative to therotation prevention hole 68. Due to these movements, the pivot guide 39and the rotation prevention hole 68 can prevent rotation of the firstlens frame 30 about the optical axis of the first lens element L1without interfering with the spherical swinging operation of the firstlens frame 30 about the spherical-swinging center A1, like the sphericalswinging operation shown in FIGS. 15, 17 and 18.

Both the spherical-swinging center A1 of the first lens frame 30 and thespherical center B1 of the guide projection 39 b lie in the firstreference plane P1 (see FIG. 12). Therefore, when the first lens frame30 is made to swing along the aforementioned second plane (a planeparallel to the second reference plane P2) from the position in theimage-stabilizing initial state shown in FIG. 14, the pivot guide 39swings about the spherical center B1 of the guide projection 39 bwithout changing the position of the spherical center B1 of the guideprojection 39 b as shown in FIG. 15. Therefore, in the state shown inFIG. 15, the point of contact of the guide projection 39 b with the pairof facing surfaces 68 a of the rotation prevention hole 68 lies in thethird reference plane P3. FIG. 15 shows a state where the first lensframe 30 is tilted toward the upper side of the imaging unit 10; thestate in which the first lens frame 30 is tilted toward the lower sideof the imaging unit 10 corresponds to the mirror image of the first lensframe 30 shown in FIG. 15. Whereas, as shown in FIGS. 16 through 18,when the first lens frame 30 is swung along the aforementioned firstplane (a plane parallel to the first reference plane P1), the pivotguide 39 moves in the swinging direction about the spherical-swingingcenter A1 while being guided by the pair of facing surfaces 68 a of therotation prevention hole 68 to thereby change the position of thespherical center B1 of the guide projection 39 b. Namely, the point ofcontact of the guide projection 39 b with the pair of facing surfaces 68a varies in the forward/rearward direction with respect to the thirdreference plane P3 and also in the leftward/rightward direction alongthe pair of facing surfaces 68 a. The depth of the rotation preventionhole 68 in the forward/rearward direction is determined so that theguide projection 39 b is prevented from coming off during the movementof the pivot guide 39 in the forward/rearward direction when the firstlens frame 30 is swung along the first reference plane P1. AlthoughFIGS. 14 through 18 each show a swing movement of the first lens frame30 in a direction along the first plane or the second plane that isparallel to the first reference plane P1 or the second reference planeP2, the first lens frame 30 can swing in directions along an infinitenumber of planes, including the first optical axis O1, in addition tothese planes.

The driver which drives the first lens frame 30 so that the first lensframe 30 performs the spherical swinging operation is an electromagneticactuator which includes two voice coil motors (VCMs). One of the twovoice coil motors is configured of a permanent magnet 81 and a coil 83which are arranged in the second quadrant V2, and the other voice coilmotor is configured of a permanent magnet 82 and a coil 84 which arearranged in the third quadrant V3. As shown in FIGS. 13 and 23, thepermanent magnets 81 and 82 planarly extend in directions on tangentplanes T1 and T2 (see FIG. 23) that are tangent to a common imaginaryspherical surface J1 about the spherical-swinging center A1.Furthermore, each magnet 81 and 82 has a flat shape, the thickness ofwhich in a direction orthogonal to the associated tangent plane T1 or T2(i.e., in the direction of a normal to the associated tangent plane T1or T2) is small compared to the length and the width thereof. Thepermanent magnet 81 is arranged along the tangent plane T1 and thepermanent magnet 82 is arranged along the tangent plane T2. The centerof the outer profile of the permanent magnet 81 corresponds to thecenter thereof in planar directions along the tangent plane T1 and alsoto the center of the permanent magnet 81 in the thickness directionthereof, which is orthogonal to the tangent plane T1. Likewise, thecenter of the outer profile of the permanent magnet 82 corresponds tothe center thereof in planar directions along the tangent plane T2 andalso to the center of the permanent magnet 82 in the thickness directionthereof, which is orthogonal to the tangent plane T2. The centers of theouter profiles of the permanent magnets 81 and 82 lie in the imaginaryspherical surface J1.

As shown in FIGS. 12, 13, 22 and 23, if a straight line K1 is defined asa straight line which passes through the center of the outer profile ofthe flat permanent magnet 81 and is parallel to (an infinite number of)normals to the tangent plane T1 (i.e., the straight line K1 is thenormal to the tangent plane T1 at the point of tangency that passesthrough the center of the outer profile of the flat permanent magnet81), the straight line K1 is nonparallel to the first optical axis O1(or the first optical axis O1′ of the first lens element L1 when thespherical swinging operation has been performed; shown simply by theparenthesized reference characters O1′ in the following descriptions);in addition, the point of intersection between the permanent magnet 81and the straight line K1 is positioned closer to the front (the objectside) than the third reference plane P3. Accordingly, the first opticalaxis O1 (O1′) or a line extended from the first optical axis O1 (O1′),and normals to the tangent plane T1 intersect each othernon-orthogonally (i.e., at angles other than right angles). Using thestraight line K1 as an example, a point of intersection C1 (see FIGS.12, 13, 22 and 23) of the straight line K1 and a line extended from thefirst optical axis O1 (O1′) is coincident with the spherical-swingingcenter A1, and a half line which extends from the point of intersectionC1, as a point of origin, along the straight line K1 (i.e., extends in adirection parallel to the normals to the tangent plane T1) and towardthe tangent plane T1 has an inclination with respect to the firstoptical axis O1 (O1′) such that the distance between the half line andthe first optical axis O1 (O1′) increases in a direction approaching theobject side. In other words, if the inclination angle of theaforementioned half line, which extends from the point of intersectionC1, as a point of origin, along the straight line K1 (i.e., extends in adirection parallel to the normals to the tangent plane T1) and towardthe tangent plane T1, with respect to a half line which extends towardthe object side from the point of intersection C1, as a point of origin,in a direction parallel to the first optical axis O1 (O1′) is designatedas D1 (see FIG. 23), the following condition is satisfied: 0°<D1<90°.Although the straight line K1 has been herein illustrated by an exampleof a normal to the tangent plane T1, this normal is not limited solelyto the straight line K1; any normal to the tangent plane T1 would alsosatisfy the above-described condition for the inclination angle D1. Inthe case of any normal to the tangent plane T1 other than the straightline K1, the point of intersection C1 would not be coincident with thespherical-swinging center A1.

Likewise, if a straight line K2 is defined as a straight line whichpasses through the center of the outer profile of the flat permanentmagnet 82 and is parallel to (an infinite number of) normals to thetangent plane T2 (i.e., the straight line K2 is the normal to thetangent plane T2 at the point of tangency that passes through the centerof the outer profile of the flat permanent magnet 82), the straight lineK2 is nonparallel to the first optical axis O1 (O1′); in addition, thepoint of intersection between the permanent magnet 82 and the straightline K2 is positioned closer to the front (the object side) than thethird reference plane P3. Accordingly, the first optical axis O1 (O1′)or a line extended from the first optical axis O1 (O1′), and normals tothe tangent plane T2 intersect each other non-orthogonally (i.e., atangles other than right angles). Using the straight line K2 as anexample, a point of intersection C2 (see FIGS. 12, 13, 22 and 23) of thestraight line K2 and a line extended from the first optical axis O1(O1′) is coincident with the spherical-swinging center A1, and a halfline which extends from the point of intersection C2, as a point oforigin, along the straight line K2 (i.e., extends in a directionparallel to the normals to the tangent plane T2) toward the tangentplane T2 has an inclination with respect to the first optical axis O1(O1′) such that the distance between the half line and the first opticalaxis O1 (O1′) increases in a direction approaching the object side. Inother words, if the inclination angle of the aforementioned half line,which extends from the point of intersection C2, as a point of origin,along the straight line K2 (i.e., extends in a direction parallel to thenormals to the tangent plane T2) and toward the tangent plane T2, withrespect to a half line which extends toward the object side from thepoint of intersection C2, as a point of origin, in a direction parallelto the first optical axis O1 (O1′) is designated by D2 (see FIG. 23),the following condition is satisfied: 0°<D2<90°. Although the straightline K2 has been herein illustrated by an example of a normal to thetangent plane T2, this normal is not limited solely to the straight lineK2; any normal to the tangent plane T2 would also satisfy theabove-described condition for the inclination angle D2. In the case ofany normal to the tangent plane T2 other than the straight line K2, thepoint of intersection C2 would not be coincident with thespherical-swinging center A1.

By satisfying the above described conditions (the arrangement of thetangent planes T1 and T2, which are defined by the normal inclinationangles D1 and D2), for the arrangement of the permanent magnets 81 and82, the distance between the permanent magnet 81 and the coil 83 and thedistance between the permanent magnet 82 and the coil 84 are eachprevented from substantially varying, which enables a stable control ofthe electromagnetic actuator when the first lens frame 30 performs thespherical swinging operation. Considering the prevention of interferenceof the electromagnetic actuator with the first lens element L1,miniaturization of the imaging unit 10, the accuracy ofimage-stabilizing driving of the first lens frame 30 by theelectromagnetic actuator and the position sensitivity of the first lensframe 30, it is preferable for the following conditions to be satisfied:40°<=D1<=80° and 40°<=D2<=80°.

In the present embodiment of the imaging unit 10, the followingequations are satisfied: D1=55° and D2=55°. Additionally, when it isassumed that the imaginary spherical surface J1 is a sphere with thepoints of intersection of the imaginary spherical surface J1 with thefirst optical axis O1 and an extension line thereof as the poles of thesphere, that circular arcs on the spherical surface which connect thepoles of the sphere are meridian lines and that circular arcs on thespherical surface which are orthogonal to the meridian lines arelatitude lines (parallels), the center of the outer profile of thepermanent magnet 81 and the center of the outer profile of the permanentmagnet 82 lie on a common latitude line (parallel) of the imaginaryspherical surface J1 (lie on a common circle about the first opticalaxis O1) (see FIGS. 22 and 23). The permanent magnet 81 has a north poleand a south pole on the opposite sides of a magnetic-pole boundary lineQ1 (see FIGS. 8 and 22) thereof, and the permanent magnet 82 has a northpole and a south pole on the opposite sides of a magnetic-pole boundaryline Q2 (see FIGS. 8 and 22) thereof. As viewed in a direction parallelto the first optical axis O1 as shown in FIG. 22, each of themagnetic-pole boundary lines Q1 and Q2 is in contact with a commonimaginary circle H1 (a latitude line on the imaginary spherical surfaceJ1) about the first optical axis O1. This arrangement of the twopermanent magnets 81 and 82 achieves a good weight balance.

Additionally, as shown in FIGS. 12 and 22, a thrust acting plane P4which lies on the straight line K1 and lies on, or is parallel to, thefirst optical axis O1 and a thrust acting plane P5 which lies on thestraight line K2 and lies on, or is parallel to, the first optical axisO1 are plane-symmetrical with respect to the first reference plane P1(with the first reference plane P1 as a plane of symmetry) and intersecteach other at angles of approximately ±30 degrees with respect to thefirst reference plane P1. Namely, intersecting angle D3 between thethrust acting planes P4 and P5 is approximately 60 degrees.

The coil 83 and the Hall sensor 85, together with the permanent magnet81, are positioned in the second quadrant V2, while the coil 84 and theHall sensor 86, together with the permanent magnet 82, are positioned inthe third quadrant V3. As shown in FIGS. 12, 13 and 23, the center ofthe outer profile of the coil 83 and the Hall sensor 85 lie on thestraight line K1; additionally, the Hall sensor 85, the permanent magnet81 and the coil 83 are aligned on the straight line K1, in that orderfrom the inner diameter side that is closer to the spherical-swingingcenter A1, and the coil 83 and the Hall sensor 85 are positioned in themagnetic field of the permanent magnet 81. The center of the outerprofile of the coil 84 and the Hall sensor 86 lie on the straight lineK2; additionally, the Hall sensor 86, the permanent magnet 82 and thecoil 84 are aligned on the straight line K2, in that order from theinner diameter side that is closer to the spherical-swinging center A1,and the coil 84 and the Hall sensor 86 are positioned in the magneticfield of the permanent magnet 82.

As shown in FIGS. 13 and 23, the coils 83 and 84 lie in the imaginaryspherical surface J2, which is greater in diameter than the imaginaryspherical surface J1 and centered on the spherical-swinging center A1.The coil 83 is formed by winding wire to lie in a tangent plane T3 (seeFIG. 23) that is tangent to the imaginary spherical surface J2 and thatis orthogonal to the straight line K1. The coil 83 planarly extendsalong the tangent plane T3 and has a flat shape, the thickness of whichin the direction of the straight line K1 (a direction of a normal to thetangent plane T1) is small compared to the length and width thereofalong the tangent plane T3. Likewise, the coil 84 is formed by windingwire to lie in a tangent plane T4 (see FIG. 23) that is tangent to theimaginary spherical surface J2 and that is orthogonal to the straightline K2. The coil 84 planarly extends along the tangent plane T4 and hasa flat shape, the thickness of which in the direction of the straightline K2 (a direction of a normal to the tangent plane T2) is smallcompared to the length and width thereof along the tangent plane T4. Thetangent plane T3 is parallel to the tangent plane T1 and the tangentplane T4 is parallel to the tangent plane T2. Accordingly, mutuallyparallel flat portions of the permanent magnet 81 and the coil 83, eachof which has a flat shape, face each other in the direction of thestraight line K1 with the planarly extending directions (the tangentplanes T1 and T3) of the permanent magnet 81 and the coil 83 beingsubstantially parallel to each other. Likewise, mutually parallel flatportions of the permanent magnet 82 and the coil 84, each of which has aflat shape, face each other in the direction of the straight line K2with the planarly extending directions (the tangent planes T2 and T4) ofthe permanent magnet 82 and the coil 84 being substantially parallel toeach other. In the present embodiment, the center of the outer profileof the coil 83 and the center of the outer profile of the coil 84 lie inthe common imaginary spherical surface J2.

When it is assumed that the imaginary spherical surface J2 is a spherewith the points of intersection of the imaginary spherical surface J2with the first optical axis O1 and an extension line thereof as thepoles of the sphere, that circular arcs on the spherical surface whichconnect the poles of the sphere are meridian lines and that circulararcs on the spherical surface which are orthogonal to the meridian linesare latitude lines (parallels), the center of the outer profile of thecoil 83 and the center of the outer profile of the coil 84 lie on acommon latitude line (parallel) of the imaginary spherical surface J2(lie on a common circle about the first optical axis O1). As viewed in adirection parallel to the first optical axis O1 as shown in FIG. 12, along axis Q3 (see FIGS. 8 and 12) of the coil 83, which is parallel tothe lengthwise (elongated) direction thereof and passes through thecenter of the pair of linear portions 83 a, and a long axis Q4 (seeFIGS. 8 and 12) of the coil 84, which is parallel to the lengthwise(elongated) direction thereof and passes through the center of the pairof linear portions 84 a, are tangent to a common imaginary circle H2 (alatitude line on the imaginary spherical surface J2) about the firstoptical axis O1.

As shown in FIGS. 12 and 22, the length W1 of the permanent magnet 81along the magnetic-pole boundary line Q1 and the length W1 of thepermanent magnet 82 along the magnetic-pole boundary line Q2 are smallerthan the length U1 of the coil 83 along the long axis Q3 thereof and thelength U1 of the coil 84 along the long axis Q4 thereof. In other words,the size of the permanent magnets 81 and 82 along the respective tangentplanes T1 and T2 on a plane extending through a latitude line of theimaginary spherical surface J1 are smaller than the size of the coils 83and 84 along the respective tangent planes T3 and T4 on a planeextending through a latitude line of the imaginary spherical surface J2.On the other hand, as shown in FIG. 23, the width W2 of the permanentmagnet 81 in a direction across the north and south poles on theopposite sides of the magnetic-pole boundary line Q1 and the width W2 ofthe permanent magnet 82 in a direction across the north and south poleson the opposite sides of the magnetic-pole boundary line Q2 are greaterthan the width U2 of the coil 83 in a direction across the pair oflinear portions 83 a and the width U2 of the coil 84 in a directionacross the pair of linear portions 84 a. In other words, the size of thepermanent magnet 81 along the tangent plane T1 on a plane extendingthrough a meridian line of the imaginary spherical surface J1 and thesize of the permanent magnet 82 along the tangent plane T2 on a planeextending through another meridian line of the imaginary sphericalsurface J1 are greater than the size of the coil 83 along the tangentplane T3 on a plane extending through a meridian line of the imaginaryspherical surface J2 and the size of the coil 84 along the tangent planeT4 on a plane extending through another meridian line of the imaginaryspherical surface J2. This structure makes it possible to maintain astate where the pair of linear portions 83 a of the coil 83 and the pairof linear portions 84 a of the coil 84 face the permanent magnet 81 andthe permanent magnet 82, respectively, within the predetermined range ofthe spherical swinging operation, the center thereof being defined bythe center of the first lens frame 30 in the image-stabilizing initialstate thereof.

As described above, the permanent magnet 81 and the permanent magnet 82are respectively arranged in the second quadrant V2 and the thirdquadrant V3 on the imaginary spherical surface J1 (which is centered onthe spherical-swinging center A1), at a position closer to the frontthan the third reference plane P3 that includes the spherical-swingingcenter A1, to be substantially symmetrical to the first reference planeP1. The coil 83 and the coil 84 are respectively arranged in the secondquadrant V2 and the third quadrant V3 on the imaginary spherical surfaceJ2 (which is centered on the spherical-swinging center A1), at aposition closer to the front than the third reference plane P3, to besubstantially symmetrical to the first reference plane P1. In addition,the Hall sensor 85 and the Hall sensor 86 are also respectively arrangedin the second quadrant V2 and the third quadrant V3 on an imaginaryspherical surface which is smaller in diameter than the imaginaryspherical surface J1 and centered on the spherical-swinging center A1,at a position closer to the front than the third reference plane P3, tobe substantially symmetrical to the first reference plane P1.

Upon the coil 83, which is positioned in the magnetic field of thepermanent magnet 81, being energized, a driving force is generated in adirection orthogonal to the pair of linear portions 83 a of the coil 83and orthogonal to the magnetic-pole boundary line Q1 of the permanentmagnet 81 according to Fleming's left-hand rule. Similarly, upon thecoil 84, which is positioned in the magnetic field of the permanentmagnet 82, being energized, a driving force is generated in a directionorthogonal to the pair of linear portions 84 a of the coil 84 andorthogonal to the magnetic-pole boundary line Q2 of the permanent magnet82 according to Fleming's left-hand rule. As shown in FIGS. 12, 13, 22and 23, a thrust axis E1 shown by a double-headed arrow represents thedirection of action of thrust (thrust force) generated by the actuator(voice coil motor), configured of the permanent magnet 81 and the coil83, in the thrust acting plane P4 that passes through the center of theouter profile of the permanent magnet 81; and a thrust axis E2 shown bya double-headed arrow represents the direction of action of thrustgenerated by the actuator (voice coil motor), configured of thepermanent magnet 82 and the coil 84, in the thrust acting plane P5 thatpasses through the center of the outer profile of the permanent magnet82. In FIGS. 12 and 22, the arrows at both ends of each thrust axis E1and E2 differ in size from each other to indicate the degree ofinclination of each thrust axis E1 and E2 relative to the thirdreference plane P3, wherein the large arrow of each thrust axis E1 andE2 denotes a thrust in an obliquely forward direction, i.e., a directiontoward the object side, and the small arrow of each thrust axis E1 andE2 denotes a thrust in an obliquely rearward direction, i.e., adirection away from the object side. The coils 83 and 84 are fixedlysupported by a body part (i.e., the housing 13) of the imaging unit 10via the cover member 32, and the permanent magnets 81 and 82 aresupported by the first lens frame 30, which is a movable member, andaccordingly, a driving force generated upon each coil 83 and 84 beingenergized acts as a force to move the first lens frame 30 in themeridian direction on the imaginary spherical surface J1. Since the twovoice coil motors (a combination of the permanent magnet 81 and the coil83 and a combination of the permanent magnet 82 and the coil 84) arearranged at different positions in the latitudinal direction on theimaginary spherical surfaces J1 and J2 (so that the intersecting angleD3 between the thrust acting planes P4 and P5 becomes approximately 60degrees), the first lens frame 30 can be made to perform the sphericalswinging operation in any arbitrary direction by a combination ofcontrolling the passage of current through the two actuators (voice coilmotors). Since the first lens frame 30 is prevented from rotating aboutthe optical axis of the first lens element L1 when performing thespherical swinging operation due to the engagement of the pivot guide 39with the rotation prevention hole 68, as described above, the first lensframe 30 is prevented from moving excessively to a point where eachpermanent magnet 81 and 82 and the associated coil 83 or 84 do not faceeach other, which makes it possible to control the position of the firstlens frame 30 at all times by the two actuators (voice coil motors).

Variation in position of the permanent magnet 81 in accordance with thespherical swinging operation of the first lens frame 30 causes theoutput of the Hall sensor 85 that faces the permanent magnet 81 to vary,and variation in position of the permanent magnet 82 in accordance withthe spherical swinging operation of the first lens frame 30 causes theoutput of the Hall sensor 86 that faces the permanent magnet 82 to vary.The position of the first lens frame 30 during the spherical swingingoperation thereof can be detected from the output variations of the twoHall sensors 85 and 86.

If the imaging unit 10, which has the above described structure, ispointed at an object located in front of the imaging unit 10, lightreflected by the object (light emanating from the photographic object)enters the first prism L11 through the incident surface L11-a afterpassing through the first lens element L1 and is reflected at asubstantially right angle by the reflection surface L11-c of the firstprism L11 and travels toward the exit surface L11-b. Subsequently, thereflected light that emerges from the exit surface L11-b of the firstprism L11 enters the second prism L12 from the incident surface L12-aafter passing through the second lens element L2, the second lens groupG2, the third lens group G3 and the fourth lens group G4, and isreflected at a substantially right angle by the reflection surface L12-cof the second prism L12 and travels toward the exit surface L12-b.Subsequently, the reflected light emerges from the exit surface L12-band is captured (received) by the imaging surface of the image sensor14. A zooming operation (power-varying operation) and a focusingoperation of the imaging optical system of the imaging unit 10 areperformed by moving the second lens group G2 and/or the third lens groupG3 along the pair of rods 22 and 23 using the first motor M1 and thesecond motor M2.

In the imaging unit 10, an image-stabilizing (image shakecorrection/shake reduction) operation is performed using the first lenselement L1 of the first lens group G1, which is positioned in front ofthe first prism L11. As described above, the image-stabilizing systemdrives the first lens frame 30 relative to the support members (the basemember 31, the cover member 32 and the sensor holder 34) that are fixedwith respect to the housing 13. An advantage of selecting the first lenselement L1 as an image-stabilizing optical element is that the imagingunit 10 can be constructed to be slim in the forward/rearward direction,even though the imaging unit 10 is equipped with an image-stabilizingsystem. For instance, unlike the present embodiment of the imaging unit10, in the case of an image-stabilizing system which moves the secondlens group G2 or the third lens group G3 in a direction orthogonal tothe second optical axis O2, securement of the space for movement of thesecond lens group frame 20 or the third lens group frame 21 and thearrangement of the driver for the second lens group frame 20 or thethird lens group frame 21 cause an increase in the space, in theforward/rearward direction, that is required in the housing 13, thuscausing an increase of the thickness of the imaging unit 10.Additionally, according to the structure of the present embodiment ofthe imaging unit 10, only the first lens element L1 is driven whenimage-stabilizing control is performed rather than the entire first lensgroup G1, and accordingly, thus there being the advantage of the movingparts being compact, so that the driving load can accordingly be small.In typical image-stabilizing systems, an entire lens group usuallydriven to cancel out image shake. Whereas, in the first lens group G1 ofthe imaging unit 10, the distance between the first lens element L1 andthe second lens element L2 is great because the first prism L11, whichserves merely as a reflector which reflects the incident light rays, isdisposed between the first lens element L1 and the second lens elementL2, each of which has a refractive power; therefore, deterioration dueto aberrations is small even though the first lens element L1 is solelydriven to perform an image-stabilizing control. Accordingly, as animaging optical system, aberrations are controlled by the entire firstlens group G1, which ranges from the first lens element L1 to the secondlens element L2; however, regarding the image-stabilizing system, onlythe first lens element L1 serves as an image-stabilizing optical elementbased on the findings that satisfactory optical performance can beachieved even if the first lens element L1 and the second lens elementL2, which are widely spaced from each other in an optical axis directionwith the first prism L11 positioned therebetween, are treated assubstantially different lens groups.

The spherical swinging operation, which is performed when the first lenselement L1 is driven to perform an image-stabilizing operation, allowsthe first lens element L1 to move widely within a small space (when theimaging unit 10 is viewed from the front along the first optical axisO1) compared with the case where the first lens element L1 moveslinearly along a plane orthogonal to the first optical axis O1.Accordingly, the image-stabilizing performance can be improved byincreasing the maximum vibration angle that an image-stabilizingoperation can accommodate while making the imaging unit 10 compact notonly with respect to the forward/rearward direction but also withrespect to the upward/downward direction and the leftward/rightwarddirection (when the imaging unit 10 is viewed from the front).

Specifically, in the imaging unit 10, with attention focused on the factthat the imaging unit 10 is a bending optical system in which the firstprism L11 is positioned behind the first lens element L1, the positionof the spherical-swinging center A1 (which is positioned on a straightline extended from the first optical axis O1), about which the firstlens frame 30 is made to swing when the spherical swinging operation isperformed, is set in the rear space 55, which is positioned behind thereflection surface L11-c. With this structure, the space at the rear ofthe first prism L11 can be effectively utilized as the installationspace for the support mechanism for the first lens frame 30, and thespherical swinging operation is achieved via a structure that issuperior in space utilization. More specifically, portions such as thepivot projection 44 (the pivot arm 41 c), the pivot recess 67 (thesensor holder 34), the leaf spring 36, the pivot guide 39 (theconnecting portion 41 b) and the rotation prevention hole 68 (the sensorholder 34), which are associated with supporting the first lens frame30, are integrated and housed in the rear space 55 as shown in FIGS. 13through 18.

As optical conditions for obtaining the effects of the sphericalswinging operation by suppressing aberration fluctuations whileachieving miniaturization of the imaging unit 10, it is desirable tosatisfy the following conditions (1) and (2):−0.6<(SC−R2)/fl<0.4  (1)SF<−0.5,  (2)

wherein SF=(R2+R1)/(R2−R1);

R1 designates the radius of curvature of the surface (the incidentsurface L1-a) closest to the object side of the front lens element(s)(the first lens element L1/at least one front lens element);

R2 designates the radius of curvature of the surface (the exit surfaceL1-b) closest to the image side of the front lens element(s);

SC designates the distance on the optical axis from the surface (theexit surface L1-b) closest to the image side of the front lenselement(s) to the spherical-swinging center (A1) of the sphericalswinging operation; and

fl designates the focal length of the front lens element(s).

The sign (+/−) of each symbol in the aforementioned conditions isdefined with respect to the direction toward the image side from theobject side being determined as positive (+).

Condition (1) specifies the position of the spherical-swinging center A1normalized to the focal length of the first lens element L1. If thelower limit of condition (1) is exceeded (less than or equal to −0.6),the distance of the spherical-swinging center A1 from the first lenselement L1 becomes excessively great, which makes it difficult tominiaturize the imaging unit 10 in the forward/rearward direction andincreases aberration fluctuations. Furthermore, if the upper limit ofcondition (1) is exceeded (equal to greater than 0.4), thespherical-swinging center A1 becomes too close to the first lens elementL1, so that the angle of deviation of the optical axis of the first lenselement L1 during driving thereof becomes small (the amount of imagedeviation becomes small), so that an effective image-stabilizing effectcannot be obtained.

Condition (2) specifies the shape of the first lens element L1. If SF isoutside the specified range of condition (2), namely, if SF is greaterthan or equal to −0.5 (i.e., SF>=−0.5), the amount of aberrationfluctuations that occur during a spherical swinging operation becomesgreat even if the position of the spherical-swinging center A1 satisfiescondition (1).

FIGS. 19, 20 and 21 show first, second and third examples of the imagingoptical system of the imaging unit 10 as actual examples which satisfyeach of the aforementioned conditions (see TABLE 1). Upper and lowerhalves of FIG. 19 show the optical arrangement of the first example ofthe imaging optical system of the imaging unit 10 when the imagingoptical system is at the wide-angle extremity and the telephotoextremity, respectively. Likewise, upper and lower halves of FIG. 20show the optical arrangement of the second example of the imagingoptical system of the imaging unit 10 when the imaging optical system isat the wide-angle extremity and the telephoto extremity, respectively,and upper and lower halves of FIG. 21 show the optical arrangement ofthe third example of the imaging optical system of the imaging unit 10when the imaging optical system is at the wide-angle extremity and thetelephoto extremity, respectively.

TABLE 1

The first example of the imaging optical system is a type of opticalsystem in which the first lens element L1 is formed as a concavemeniscus lens wherein the incident surface L1-a is a convex surface andthe exit surface L1-b is a concave surface (SF<−1). The second exampleof the imaging optical system is a type of optical system in which thefirst lens element L1 is formed as a plano-concave lens wherein theincident surface L1-a is a flat surface and the exit surface L1-b is aconcave surface (SF=−1). The third example of the imaging optical systemis a type of optical system in which the first lens element L1 is formedas a biconcave lens, wherein each of the incident surface L1-a and theexit surface L1-b is a concave surface (SF>−1).

Likewise with the examples shown in FIGS. 19, 20 and 21, it is desirablefor the surface closest to the image plane (i.e., the exit surface L1-b)of the front lens element, which is driven to perform animage-stabilizing operation, to be a concave surface. Specifically, ifthe surface closest to the image plane of the front lens element isformed as a part of an imaginary spherical surface that is centeredabout the spherical-swinging center A1, the positional relationshipbetween the surface closest to the image plane (the exit surface L1-b)of the front lens element and the focal point of the front lens elementdoes not optically change even if a spherical swinging operation aboutthe spherical-swinging center A1 is performed, which makes it possibleto prevent coma which would otherwise be caused by this surface fromoccurring during the spherical swinging operation.

Additionally, including also the case of the incident surface L1-a beinga flat surface like in the second example, it is desirable for thesurface (the incident surface L1-a) closest to the object side of thefront lens element (the first lens element L1), which performs theimage-stabilizing operation, to be smaller in power (refractive power)than the surface (the exit surface L1-b) closest to the image side ofthe front lens element (the first lens element L1).

Instead of a single lens element such as the first lens element L1, acemented lens or a plurality of lens elements can alternatively be usedas the front lens element that is driven to perform an image-stabilizingoperation. In the case where a plurality of front lens elements areused, it is desirable for the plurality of front lens elements to beintegrally driven as a single sub-lens group when an image-stabilizingoperation is performed to prevent optical performance fromdeteriorating. Additionally, in such a case, R1, R2, SC and fl in theaforementioned conditions (1) and (2) would be replaced as follows: R1designates the radius of curvature of the surface (incident surface)closest to the object side of the frontmost lens element that is closestto the object side of the plurality of front lens elements; R2designates the radius of curvature of the surface (exit surface) closestto the image side of the rearmost lens element that is closest to theimage side of the plurality of lens elements; SC designates the distanceon the optical axis from the surface (exit surface) closest to the imageside of the rearmost lens element that is closest to the image side ofthe plurality of lens elements to the spherical-swinging center (A1) ofthe spherical swinging operation; and fl designates the combined focallength of the plurality of lens elements.

Regarding the arrangement of the image-stabilizing driver which drivesthe first lens frame 30 (the first lens element L1) to cancel out imageshake, due to the arrangement of the permanent magnets 81 and 82 on theimaginary spherical surface J1 about the spherical-swinging center A1and the arrangement of the coils 83 and 84 on the imaginary sphericalsurface J2 about the spherical-swinging center A1, the distance betweenthe permanent magnet 81 and the coil 83 and the distance between thepermanent magnet 82 and the coil 84 vary little, respectively, whichmakes it possible to achieve a stable image-stabilizing control withhigh precision when the first lens frame 30 is driven to perform thespherical swinging operation about the spherical-swinging center A1.

Additionally, in the case where a voice coil motor(s) is used as theimage-stabilizing driver, one of a permanent magnet(s) and a coil(s)becomes a movable element which moves with the first lens frame 30 andthe other a fixed element (stationary element). In the presentembodiment of the imaging unit 10, moving-magnet type voice coil motorsin which the permanent magnets 81 and 82 are held by the movable firstlens frame 30 are used, and a space-efficient component arrangementwhich is suitable therefor has been achieved. First of all, the fartherthe installation positions of the permanent magnets 81 and 82, which aremovable elements, from the spherical-swinging center A1, the greater themoving amount of each permanent magnet 81 and 82 when the first lensframe 30 performs the spherical swinging operation; additionally, as themoving amount of each permanent magnet 81 and 82 increases, theclearance between each permanent magnet and the fixed members (the basemember 31, the cover member 32, the sensor holder 34, etc.) whichsurround the first lens frame 30 needs to be increased. Consequently,the permanent magnets 81 and 82, which are provided as movable elements,are arranged as close to the spherical-swinging center A1 as possible,as much as the size constraints thereof allow (the size constraintsmainly being the size of the permanent magnet 81 in the surfacedirection defined by the length W1 of the permanent magnet 81 along themagnetic-pole boundary line Q1 and the width W2 of the permanent magnet81 in a direction orthogonal to the magnetic-pole boundary line Q1, andthe size of the permanent magnet 82 in the surface direction defined bythe length W1 of the permanent magnet 82 along the magnetic-poleboundary line Q2 and the width W2 of the permanent magnet 82 in adirection orthogonal to the magnetic-pole boundary line Q2).

Due to dimensional conditions such as the length U1 of the coil 83 alongthe long axis Q3 and the length U1 of the coil 84 along the long axis Q4being greater than the length W1 of the permanent magnet 81 along themagnetic-pole boundary line Q1 and the length W1 of the permanent magnet82 along the magnetic-pole boundary line Q2, respectively, it isdifficult to arrange the coils 83 and 84 at inner positions closer tothe spherical-swinging center A1 than the permanent magnets 81 and 82.Hence, the coils 83 and 84 are arranged on the radially outer side thatis farther from the spherical-swinging center A1 than the permanentmagnets 81 and 82 in directions along the straight lines K1 and K2,respectively. Unlike the permanent magnets 81 and 82, the coils 83 and84 are fixed elements that do not move during the spherical swingingoperation, and accordingly, it is not required to respectively secure aclearance between the coils 83 and 84 and the peripheral members thereofwhich is determined in consideration of the operation of the coils 83and 84, which does not easily increase the size of the imaging unit 10even when the coils 83 and 84 are arranged on the radially outside ofthe permanent magnets 81 and 82.

In addition, considering the fact that the Hall sensors 85 and 86 aresmaller in size than either of the permanent magnets 81 and 82 and thecoils 83 and 84, the Hall sensors 85 and 86 are arranged at innerpositions closer to the spherical-swinging center A1 than the permanentmagnets 81 and 82 in the directions along the straight lines K1 and K2,respectively. As can be seen from FIG. 13, the pair of sensor supportprojections 61 and 62 that support the small Hall sensors 85 and 86 canbe inserted into the narrow space surrounded by the lens holding portion40 (the circular frame portion 40 b) and the pair of magnet holdingportions 42 and 43 of the first lens frame 30 and the spring supportportion 58 of the base member 31, so that the small Hall sensors 85 and86 are space-efficiently arranged. In addition, the Hall sensors 85 and86 are fixed at positions adjacent to the inner sides of the permanentmagnets 81 and 82, and this arrangement of the Hall sensors 85 and 86 isadvantageous with regard to detection accuracy, in addition to spaceefficiency, compared with the case where the Hall sensors 85 and 86 areinstalled on the outer side of the coils 83 and 84.

As illustrated above, the above described structure in which the movableelement and the fixed element of each voice coil motor arespace-efficiently arranged in an advantageous order, in radialdirections (directions along the straight lines K1 and K2) with respectto the spherical-swinging center A1, suitable for their respectiveconditions contributes to compactization (miniaturization) of theimaging unit 10.

In addition, the permanent magnets 81 and 82, the coils 83 and 84 andthe Hall sensors 85 and 86 are installed in the side space 56 (thesecond quadrant V2 and the third quadrant V3) in the base member 31. Theside space 56 is formed in a section (first section) on the oppositeside of the second reference plane P2 from the side on which thetraveling direction of the light rays deflected by the first prism L11(the traveling direction of the second optical axis O2), and none of theoptical elements of the imaging optical system which are positionedoptically rearward from the first prism L11 (rightward with respect toFIG. 7) are arranged in the side space 56, and accordingly, thearrangement of the permanent magnets 81 and 82, the coils 83 and 84 andthe Hall sensors 85 and 86 is not easily subjected to spacerestrictions. For instance, it is possible to drive the first lenselement L1 even if the permanent magnets 81 and 82 and the coils 83 and84 are arranged in a second section on the right side of the secondreference plane P2 which includes the first quadrant V1 and the fourthquadrant V4; however, the second lens element L2 is positioned in thefirst quadrant V1 and the fourth quadrant V4 at a position adjacent tothe exit surface L11-b of the first prism L11, so that in this casethere is a problem of it being difficult to secure space for installingthe entire electromagnetic actuator without interfering with the secondlens element L2. Whereas, there is no such a restriction in thearrangement of the illustrated embodiment in which a combination of thepermanent magnet 81 and the coil 83 provided in the second quadrant V2and a combination of the permanent magnet 82 and the coil 84 provided inthe third quadrant V3.

Additionally, the second lens group G2 and the third lens group G3 thatare movable along the second optical axis O2 are provided on an opticalpath extending from the first prism L11, the first motor M1 and thesecond motor M2, which constitute members of the drive mechanism formoving the second lens group G2 and the third lens group G3 along thesecond optical axis O2, contain metal parts, and the pair of rods 22 and23 are also metal parts. If these metal parts are made of a magneticmaterial and positioned near the electromagnetic actuator, there is apossibility of such metal parts exerting an adverse influence on theimage-stabilizing driving operation of the electromagnetic actuator.Specifically, in the moving-magnet electromagnetic actuator in which thepermanent magnets 81 and 82 are supported on the moveable first lensframe 30, in order to make the electromagnetic actuator perform drivecontrol with high precision, it is required to remove the adverseinfluence caused by external magnetic materials on the magnetic fieldsof the permanent magnets 81 and 82. The permanent magnets 81 and 82 andthe coils 83 and 84 that are arranged in the second quadrant V2 and thethird quadrant V3 are farther in distance from each motor M1 and M2 andeach rod 22 and 23 than in the case where the permanent magnets 81 and82 and the coils 83 and 84 were to be arranged in the first quadrant V1and the fourth quadrant V4; therefore, the parts of the motors M1 and M2and the rods 22 and 23 do not easily adversely-influence the driving ofthe electromagnetic actuator even if these parts contain magneticmetals.

The permanent magnets 81 and 82 and the coils 83 and 84, whichconstitute actuators (voice coil motors), are shaped and arranged toextend in planar directions along the tangent planes T1 and T2 of theimaginary spherical surface J1 (centered about the spherical-swingingcenter A1) and the tangent planes T3 and T4 of the imaginary sphericalsurface J2 (centered about the spherical-swinging center A1),respectively. As can be seen from the thrust axes E1 and E2 shown inFIGS. 12, 13, 22 and 23, the thrust force generated by the actuator,configured of the permanent magnet 81 and the coil 83, acts on the firstlens frame 30 as a force along the tangent plane T1 in which thepermanent magnet 81 lies, and the thrust force generated by theactuator, configured of the permanent magnet 82 and the coil 84, acts onthe first lens frame 30 as a force along the tangent plane T2 in whichthe permanent magnet 82 lies, so that the first lens frame 30, thespherical-swinging center A1 of which is positioned at the center of theimaginary spherical surface J1, can be made to perform the sphericalswinging operation smoothly with high precision.

The tangent planes T1 and T2 of the imaginary spherical surface J1, inwhich the permanent magnets 81 and 82 are respectively arranged toextend planarly, and the tangent planes T3 and T4 of the imaginaryspherical surface J2, in which the coils 83 and 84 are respectivelyarranged to extend planarly, are nonparallel to either a plane parallelto the first optical axis O1 or a plane (the third reference plane P3)orthogonal to the first optical axis O1. In addition, as describedabove, the inclination angle D1 of the straight line K1 (which extendsin a direction normal to the tangent plane T1 and T3 (in a precisesense, a half line which extends along the straight line K1 from thepoint of intersection C1, as a point of origin, toward the tangentplanes T1 and T3)) relative to the optical axis of the first lenselement L1 (in a precise sense, a half line which extends parallel tothe first optical axis O1 (O1′) from the point of intersection C1, as apoint of origin, toward the object side) is greater than 0 degrees andsmaller than 90 degrees (0°<D1<90°) (see FIG. 23), and the inclinationangle D2 of the straight line K2 (which extends in a direction normal tothe tangent plane T2 and T4 (in a precise sense, a half line whichextends along the straight line K2 from the point of intersection C2, asa point of origin, toward the tangent planes T2 and T4)) relative to theoptical axis of the first lens element L1 (in a precise sense, a halfline which extends parallel to the first optical axis O1 (O1′) from thepoint of intersection C2, as a point of origin, toward the object side)is greater than 0 degree and smaller than 90 degrees (0°<D2<90°) (seeFIG. 23).

If the inclination angle D1 of the straight line K1 and the inclinationangle D2 of the straight line K2 are 0 degrees, the permanent magnetsand coils, of the electromagnetic actuator, would planarly extendparallel to the third reference plane P3. In this configuration, thearrangement of the flat permanent magnets and coils would be such thatthe profiles of the front projections thereof are the greatest in sizewhen viewed along the first optical axis O1, and accordingly, arrangingsuch an electromagnetic actuator around the first lens element L1 wouldcause an increase in size of the imaging unit. If the inclination angleD1 of the straight line K1 and the inclination angle D2 of the straightline K2 are 90 degrees, the permanent magnets and coils, of theelectromagnetic actuator, would planarly extend along a plane orthogonalto the third reference plane P3. In this configuration, when viewedalong the first optical axis O1, the profiles of the thin sides(thickness portions) of the flat permanent magnets and coils would beviewed, so that the profile of the front projection of each actuatoritself is small, however the distance of each actuator from thespherical-swinging center A1 along the third reference plane P3 becomesgreat. If the case where a configuration in which the inclination angleD1 of the straight line K1 and the inclination angle D2 of the straightline K2 are 90 degrees is applied to the above illustrated embodiment ofthe imaging unit 10, each permanent magnet 81 and 82 would be positionedat a point of intersection between the third reference plane P3 and theimaginary spherical surface J1 (or at a point in front of or behind thispoint of intersection) in FIGS. 13 and 23, so that the permanent magnet81 and the coil 83 would further project obliquely leftward and upwardfrom the positions thereof shown in FIG. 12 and the permanent magnet 82and the coil 84 would further project obliquely leftward and downwardfrom the positions thereof shown in FIG. 12. This would result in anincrease in size of the imaging unit compared with the presentembodiment of the imaging unit 10. Additionally, if each of theinclination angle D1 of the straight line K1 and the inclination angleD2 of the straight line K2 is greater than 90 degrees, the permanentmagnets and the coils that constitute the electromagnetic actuator wouldbe positioned behind the third reference plane P3 in the rearwarddirection along the first optical axis O1. If the electromagneticactuator configured of the permanent magnets 81 and 82 and the coil 83and 84 are positioned behind the third reference plane P3, the imagingunit 10 increases in size in the forward/rearward direction.Specifically, the distance between the first lens element L1 and theelectromagnetic actuator in the forward/rearward direction increases,which causes a considerable increase in size of the first lens frame 30,thus being disadvantageous with regard to space utilization.

Unlike these comparative examples, in the preset embodiment of theimaging unit 10, by making each of the inclination angle D1 of thestraight line K1 and the inclination angle D2 of the straight line K2greater than 0 degrees and less than 90 degrees, the profile of thefront projection of each of the two actuators is reduced in size and theamount of projection of each of the two actuators in the direction alongthe first optical axis O1 is also reduced, which makes it possible toachieve a compact image-stabilizing driver which is superior in spaceefficiency.

The conditions 40°<D1<80° and 40°<D2<80° have been described as a moredesirable condition for the inclination angle D1 of the straight line K1and the inclination angle D2 of the straight line K2. Although dependingon the diameter of the first lens element L1 and the size of eachpermanent magnet 81 and 82, the permanent magnets 81 and 82 can bearranged at positions close to the first lens element L1 withoutinterfering with the first lens element L1 by setting each of theinclination angle D1 and the inclination angle D2 at 40 degrees or more.For instance, in the present embodiment of the imaging unit 10, the edgeof each permanent magnet 81 and 82 and the edge of the first lenselement L1 are close to each other, as shown in FIGS. 13 and 23, so thatit can be seen that the first lens element L1 and the permanent magnets81 and 82 are arranged on the imaginary spherical surface J1 in a spaceefficient manner. If each of the inclination angle D1 and theinclination angle D2 is set to less than 40 degrees (for example 30degrees), the permanent magnets 81 and 82 overlap the installation areaof the first lens element L1, which makes it difficult to arrange thepermanent magnets 81 and 82. Conversely, if each of the inclinationangle D1 and the inclination angle D2 is set to greater than 80 degrees,the effect of miniaturization of the imaging unit in the direction alongthe third reference plane P3 is weakened.

As described above, the pivot guide 39 and the rotation prevention hole68 prevents rotation of the first lens frame 30 about the optical axisof the first lens element L1 while supporting the first lens frame 30 ina manner to allow the first lens frame 30 to perform the sphericalswinging operation. If the first lens frame 30 is allowed to rotatefreely relative to the base member 31 and the sensor holder 34 withoutthe imaging unit 10 being provided with a rotation preventer like theabove described rotation preventer, there is a possibility of thepositions of the permanent magnets 81 and 82 deviating largely relativeto the coils 83 and 84 and the Hall sensors 85 and 86 that are fixedlysupported. If an excessive deviation occurs, appropriate thrust forcesmay not be appropriately applied to the first lens frame 30 by thepermanent magnets 81 and 82 and the coils 83 and 84, or the position ofthe first lens frame 30 may not be precisely detected by the Hallsensors 85 and 86, which makes it difficult to perform image-stabilizingcontrol. By providing at least three actuators and corresponding atleast three detection sensors at different circumferential positionsabout the first optical axis O1, image-stabilizing control may bepossible even if the first lens frame 30 rotates about the optical axisof the first lens element L1. However, in the imaging unit 10, there isthe constraint of it being impossible to secure a large space on theside of the first and fourth quadrants V1 and V4, on which the secondoptical axis O2 extends; accordingly, it is difficult to install three(or more) actuators and corresponding three (or more) detection sensorsaround the first lens element L1. Therefore, the installation of three(or more) actuators and corresponding three (or more) detection sensorsaround the first lens element L1 would inevitably cause a substantialincrease in size of the imaging unit 10. Accordingly, arranging the twoactuators (i.e., the voice coil motor configured of the permanent magnet81 and the coil 83 and the voice coil motor configured of the permanentmagnet 82 and the coil 84) and the Hall sensors 85 and 86 into thesecond quadrant V2 and the third quadrant V3, respectively, achievessuperior space efficiency. Furthermore, by providing a rotationpreventer for the first lens frame 30, it is possible to prevent thefirst lens frame 30 from behaving beyond the controllable range of eachactuator while using the space-efficient driver, which makes it possibleto make the first lens frame 30 perform the spherical swinging operationwith stability and precision.

The rotation preventer that prevents rotation of the first lens frame 30when the first lens frame 30 performs the spherical swinging operationis not limited to the above illustrated embodiment (first embodiment) ofthe rotation preventer that has been illustrated with reference to FIGS.1 through 24B. Other embodiments (second through eleventh embodiments)of the rotation preventer for the first lens frame 30 will be discussedhereinafter.

FIGS. 25A through 28C show modified examples of the pivot guide that isinserted into the rotation prevention hole 68 of the sensor holder 34,wherein the guide projection of the pivot guide has a different shapefrom that of the pivot guide 39 in the first embodiment.

Substantially the entirety of the guide projection 39 b of the pivotguide 39 in the first embodiment of the rotation preventer shown inFIGS. 24A and 24B has the shape of a sphere, whereas a pivot guide 139which is provided as a member of the second embodiment of the rotationpreventer shown in FIGS. 25A and 25B is provided with a guide projection(projection as an element of the rotation preventer) 39 d, having aspherical barrel shape wherein the end (the lower end with respect toFIG. 25B) of the pivot guide 139 on the opposite side thereof from thebase 39 a is flattened while the remainder thereof is spherical inshape. Similar to the guide projection 39 b of the pivot guide 39 in thefirst embodiment of the rotation preventer, the guide projection 39 d isinserted into the rotation prevention hole 68 with the spherical surfaceof the guide projection 39 d being in contact (point contact) with thepair of facing surfaces 68 a. Accordingly, it is possible to preventrotation of the first lens frame 30 about the optical axis of the firstlens element L1 by the insertion of the guide projection 39 d of thepivot guide 139 into the rotation prevention hole 68 while allowing thefirst lens frame 30 to perform the spherical swinging operation.

A pivot guide 239 in the third embodiment of the rotation preventershown in FIGS. 26A, 26B and 26C is provided with a cylindrical guideprojection (as an element of the rotation preventer) 39 e which isformed into a cylinder having an axis Z1. The axis Z1 of the cylindricalguide projection 39 e extends in a direction orthogonal to the axis ofthe base 39 a (in a direction parallel to the pair of facing surfaces 68a of the rotation prevention hole 68). The guide projection 39 e isformed into a cylinder having a constant diameter about the axis Z1. Thecylindrical surface, centered about the axis Z1, of the guide projection39 e is in contact with the pair of facing surfaces 68 a at all times.

A pivot guide 339 in the fourth embodiment of the rotation preventershown in FIGS. 27A, 27B and 27C is provided with a partial-cylindricalguide projection (as an element of the rotation preventer) 39 f which isformed into a cylinder (having a D-shaped cross section) the peripheralsurface of which is partly flattened (the end of the partial-cylindricalguide projection 39 f on the opposite side thereof from the base 39 a isflattened).

A pivot guide 439 in the fifth embodiment of the rotation preventershown in FIGS. 28A, 28B and 28C is provided with a partial-cylindricalguide projection (as an element of the rotation preventer) 39 g having adouble-D (double-D cut) cross section. The end (fixed end) of the guideprojection 39 g which is connected to the base 39 a and the opposite endof the guide projection 39 g from the fixed end are formed into a pairof parallel planes, and this pair of parallel planes are connected byportions (two partial-cylindrical surfaces) of a cylindrical surfacewith the axis Z1 as a center thereof.

In addition to the perfect-cylindrical guide projection 39 e shown inFIGS. 26A, 26B and 26C, opposite sides of each of thepartial-cylindrical guide projections 39 f and 39 g, which arerespectively in contact with the pair of facing surfaces 68 a of therotation prevention hole 68, are formed as circular arc surfaces, thecurvature centers of which are coincident with each other. Unlike thepartial-cylindrical guide projections 39 f and 39 g, in the case wherethe curvature centers of the opposite sides (circular arc surfaces) ofthe guide projection that are respectively in contact with the pair offacing surfaces 68 a are not coincident with each other, there is apossibility of motion of the first lens frame 30 in the sphericalswinging operation deteriorating, so that it is desirable that the guideprojection be formed as the guide projection 39 f or 39 b.

Each guide projection 39 e, 39 f and 39 g which is inserted into therotation prevention hole 68 prevents rotation of the first lens frame 30about the optical axis of the first lens element L1 by being heldbetween the pair of facing surfaces 68 a. On the other hand, each guideprojection 39 e, 39 f and 39 g can slide on and along the pair of facingsurfaces 68 a and swing about the axis Z1 of the cylindrical portion, asa swinging center (fulcrum), and these movements allow the first lensframe 30 to perform the spherical swinging operation. Accordingly, eachguide projection 39 e, 39 f and 39 g functions in a similar manner toeach of the guide projections 39 b and 39 d in the first and secondembodiments of the rotation preventers.

The spherical outer surface of each of the guide projections 39 b and 39d in the first and second embodiments of the rotation preventers is inpoint contact with the pair of facing surfaces 68 a of the rotationprevention hole 68, whereas the cylindrical outer surface of each of theguide projections 39 e, 39 f and 39 g in the third through fifthembodiments of the rotation preventers is in line contact with the pairof facing surfaces 68 a of the rotation prevention hole 68 in adirection along the axis Z1 of the cylindrical portion. In any of theseembodiments (the first through fifth embodiments), the formation of thecontacting portion of the guide projection (39 b, 39 d, 39 e, 39 f or 39g) with the pair of facing surfaces 68 a into a nonplanar surface suchas a spherical surface or a circular arc surface (cylindrical surface)makes it possible to allow the guide projection to slide and swingnaturally without stress in directions other than the direction whichconnects the pair of facing surfaces 68 a (widthwise direction of therotation prevention hole 68) while being prevented from moving in thisconnecting direction, which allows the first lens frame 30 to performthe spherical swinging operation smoothly. In the case where therotation preventer is of a type in which the guide projection of thepivot guide is in line contact with the pair of facing surfaces 68 a ofthe rotation prevention hole 68, the rotation preventer becomes moresubject to error in part accuracy since the range of line contact of theguide projection with the pair of facing surfaces 68 a increases; hence,it is desirable for the axial length of the cylindrical portion of eachguide projection 39 e, 39 f and 39 g to be short. More specifically, itis desirable for the axial length of each guide projection 39 e, 39 fand 39 g to be slightly greater than the diameter of the base 39 a andsmaller than the diameter of the flange 39 c.

As shown in the sixth embodiment of the rotation preventer of FIGS. 29and 30, the guide projection which is inserted into the rotationprevention hole 68 of the sensor holder 34 can be formed as a guideprojection (as an element of the rotation preventer) 39 h that is formedintegral with the first lens frame 30. Similar to the guide projection39 e in the third embodiment of the rotation preventer, the guideprojection 39 h has a cylindrical outer shape about an axis Z2 along thefirst reference plane P1 and projects rearward (toward the side oppositeto the object side) from the connecting portion 41 b that constitutes aportion of the support portion 41 of the first lens frame 30. As shownin FIGS. 29 and 30, the guide projection 39 h which is inserted into therotation prevention hole 68 of the sensor holder 34 prevents rotation ofthe first lens frame 30 about the optical axis of the first lens elementL1 by being held between the pair of facing surfaces 68 a. On the otherhand, the guide projection 39 h can slide on and along the pair offacing surfaces 68 a and swing about the axis Z2 as a swinging center(fulcrum), and these movements allow the first lens frame 30 to performthe spherical swinging operation. The shape of the guide projection,which is formed integral with the first lens frame 30, is not limited toa cylindrical shape like that of the guide projection 39 h. The guideprojection can be shaped into a sphere in the same manner as the guideprojection 39 b (see FIGS. 24A and 24B), a spherical barrel in the samemanner as the guide projection 39 d (see FIGS. 25A and 25B), a partialcylinder (see FIGS. 27A, 27B, 27C, 28A, 28B and 28C) which is formed asa cylinder with a part or parts thereof cut off, or can be formed intoan alternative shape.

In the seventh embodiment of the rotation preventer shown in FIGS. 31through 34, a guide shaft (as an element of the rotation preventer) 539which is provided in (embedded in) the first lens frame 30 and arotation prevention hole (projection insertion portion) 568 which isformed in the sensor holder 34 constitute a rotation preventer whichprevents rotation of the first lens frame 30 about the optical axis ofthe first lens element L1 while allowing the first lens frame 30 toperform the spherical swinging operation. The guide shaft 539 has acylindrical surface, the diameter of which is constant acrosssubstantially the entire length thereof in the axial direction. Theguide shaft 539 is positioned on the left-hand side of thespherical-swinging center A1, and the axis Z3 of the guide shaft 539lies on the first reference plane P1 (see FIGS. 32 and 33). In addition,as shown in FIGS. 33 and 34, when the first lens frame 30 is in theimage-stabilizing initial state, the axis Z3 of the guide shaft 539 lieson the third reference plane P3, and therefore has no inclinationrelative to the forward/rearward direction. The rotation prevention hole568 is formed in the base plate 60 of the sensor holder 34 and is formedinto a U-shaped recess which is open toward the rear, and the rotationprevention hole 568 is provided with a pair of facing protrusions(holding portions) 568 a which face each other with the first referenceplane P1 positioned therebetween. As shown in FIGS. 31 and 32, eachfacing protrusion 568 a is in the shape of a trapezoidal protrusion, thewidth thereof reducing in a direction approaching the first referenceplane P1, and the pair of facing protrusions 568 a hold the guide shaft539 from both sides thereof at the tips of the pair of facingprotrusions 568 a, where the distance therebetween is minimum. The widthof the pair of facing protrusions 568 a in the axial direction of theguide shaft 539 (in the leftward/rightward direction of the imaging unit10) is smaller than the length of the guide shaft 539, and the pair offacing protrusions 568 a are in contact with a portion of the guideshaft 539 in the axial direction thereof (see FIGS. 32 and 34). The tipof each facing protrusion 568 a can be shaped into a flat surface thatcomes in line contact with the guide shaft 539, or a circular arcsurface which comes in point contact with the guide shaft 539. Rotationof the first lens frame 30 about the optical axis of the first lenselement L1 is prevented by the guide shaft 539 being held between thepair of facing protrusions 568 a.

As shown in FIGS. 31, 32 and 34, the rotation prevention hole 568 isopen in the axial direction of the guide shaft 539 (theleftward/rightward direction of the imaging unit 10) to allow the guideshaft 539 to move in the axial direction thereof while sliding againstthe pair of facing protrusions 568 a of the rotation prevention hole568. As shown in FIGS. 31, 33 and 34, the size of the rotationprevention hole 568 in the depthwise direction thereof (theforward/rearward direction of the imaging unit 10) is greater than thediameter of the guide shaft 539 to allow the guide shaft 539 to alsoslide in the depthwise direction of the rotation prevention hole 568(the forward/rearward direction of the imaging unit 10) relative to therotation prevention hole 568. In addition, the guide shaft 539 can swing(rotate) about the axis Z3, as a swinging center (fulcrum) relative tothe rotation prevention hole 568. Due to these movements, the guideshaft 539 and the rotation prevention hole 568 do not interfere with thespherical swinging operation of the first lens frame 30.

In the first through seventh embodiments of the rotation preventers, ina state where the first lens frame 30 is in the image-stabilizinginitial state, the mutually contacting portions between the first lensframe 30 (39 b, 39 d, 39 e, 39 f, 39 g, 39 h, 539) and the sensor holder34 (68 a, 568 a) that are for preventing rotation of the first lensframe 30 about the optical axis of the first lens element L1 lie in thethird reference plane P3 (a plane which passes through thespherical-swinging center A1 and is orthogonal to the first optical axisO1); however, these contacting portions can also be arranged atpositions other than in the third reference plane P3 in theforward/rearward direction. Modified embodiments having such anarrangement are shown as an eighth embodiment of the rotation preventerin FIG. 35 and a ninth embodiment of the rotation preventer in FIGS. 36and 37.

The eighth embodiment of the rotation preventer shown in FIG. 35prevents rotation of the first lens frame 30 about the optical axis ofthe first lens element L1 while allowing the first lens frame 30 toperform the spherical swinging operation by an insertion of a pivotguide 639 which is provided on the first lens frame 30 into a rotationprevention hole (projection insertion portion) 668 of the sensor holder34. The rotation prevention hole 668 is a hole elongated in theleftward/rightward direction. More specifically, the length of therotation prevention hole 668 in the leftward/rightward direction, whichcorresponds to the distance along a central line which connects a pairof end portions 668 b of the rotation prevention hole 668, is greaterthan the width of the rotation prevention hole 668 in theupward/downward direction, which is defined by the distance between apair of facing surfaces (holding portions) 668 a (only one of which isshown in FIG. 35) of the rotation prevention hole 668. Although thearrangement of the rotation prevention hole 668 corresponds to thearrangement of the rotation prevention hole 68 of the first embodimentof the rotation preventer as viewed from the front along the firstoptical axis O1, the rotation prevention hole 668 is formed at aposition in front of the third reference plane P3, unlike the rotationprevention hole 68. Similar to the pivot guide 39 in the firstembodiment of the rotation preventer, the pivot guide 639 is providedwith a base 639 a which is embedded in the connecting portion 41 b ofthe first lens frame 30, a spherical guide projection (as an element ofthe rotation preventer) 639 b which is inserted into the rotationprevention hole 668, and a large-diameter flange 639 c which ispositioned between the base 639 a and the guide projection 639 b todefine the amount of projection of the guide projection 639 b. In theimage-stabilizing initial state of the first lens frame 30 shown in FIG.35, a spherical center B2 of the spherical guide projection 639 b ispositioned in front of the third reference plane P3. The guideprojection 639 b comes in contact (point contact) with the pair offacing surfaces 668 a at the same position as the spherical center B2 inthe forward/rearward direction to prevent rotation of the first lensframe 30 about the optical axis of the first lens element L1. Inaddition, when the first lens frame 30 performs the spherical swingingoperation about the spherical-swinging center A1, neither slidingmovements of the guide projection 639 b against the pair of facingsurfaces 668 a nor swinging movements of the guide projection 639 babout the spherical center B2 as a swinging center (fulcrum) interferewith the spherical swinging operation. Even when the position of thepivot guide 639 in the forward/rearward direction varies according tothe spherical swinging operation of the first lens frame 30, the pointof contact between the guide projection 639 b and the pair of facingsurfaces 668 a is maintained positioned in front of the third referenceplane P3.

The ninth embodiment of the rotation preventer shown in FIGS. 36 and 37prevents rotation of the first lens frame 30 about the optical axis ofthe first lens element L1 while allowing the first lens frame 30 toperform the spherical swinging operation by an insertion of a guideshaft (projection) 739 which is provided in (embedded in) the first lensframe 30 via a rotation prevention hole (projection insertion portion)768 of the sensor holder 34. Similar to the rotation prevention hole 568in the seventh embodiment of the rotation preventer (shown in FIGS. 31through 34), the rotation prevention hole 768 is provided with a pair offacing protrusions (holding portions) 768 a which hold a portion of theguide shaft 739 in the axial direction thereof. The axis Z4 of the guideshaft 739 lies in the first reference plane P1, as with the guide shaft539 in the seventh embodiment of the rotation preventer; however, unlikethe guide shaft 539, the axis Z4 of the guide shaft 739 is inclined tothe third reference plane P3 in the image-stabilizing initial state ofthe first lens frame 30 shown in FIGS. 36 and 37. More specifically, asshown in FIG. 37, the spherical-swinging center A1 lies on an extensionof the axis Z4 of the guide shaft 739, and the axis Z4 is inclinedforward from the third reference plane P3 as the distance from thespherical-swinging center A1 increases. Additionally, the guide shaft739 comes in contact with the pair of facing protrusions 768 a of therotation prevention hole 768 at a position in front of the thirdreference plane P3 to be supported in a manner to be capable of slidingin the leftward/rightward direction, in which the guide shaft 739extends, sliding in the depthwise direction of the rotation preventionhole 768 (the forward/rearward direction of the imaging unit 10) andswinging (rotating) about the axis Z4 as a swinging center (fulcrum).This relationship between the guide shaft 739 and the rotationprevention hole 768 prevents rotation of the first lens frame 30 aboutthe optical axis of the first lens element L1 while allowing the firstlens frame 30 to perform the spherical swinging operation about thespherical-swinging center A1.

In the case where a projection which is long in the axial directionthereof such as the guide shafts 539 and 739 in the seventh and ninthembodiments of the rotation preventer is used as an element of therotation preventer, it is desirable that the spherical-swinging centerA1 be located on an extension of the axis of the long projection.Satisfying this condition makes it possible to achieve a stablerotation-prevention control when the first lens frame 30 performs thespherical swinging operation and also has the effect of achievingexcellent followability of the rotation preventer with respect to thespherical swinging operation; each of the guide shafts 539 and 739satisfies this condition.

In any of the above illustrated first through ninth embodiments of therotation preventers, the pivot guide and the guide shaft that constitutethe rotation preventer of the first lens frame 30 are arranged in thefirst reference plane P1, and the pair of facing surfaces or the pair offacing protrusions of the rotation prevention hole that hold the pivotguide or the guide shaft are arranged to be substantially symmetrical tothe first reference plane P1. If the voice coil motor configured of thepermanent magnet 81 and the coil 83 and the voice coil motor configuredof the permanent magnet 82 and the coil 84 are regarded as the firstactuator and the second actuator, respectively, the thrust acting planeP4, which includes the thrust axis E1 of the first actuator and thespherical-swinging center A1, and the thrust acting plane P5, whichincludes the thrust axis E2 of the second actuator and thespherical-swinging center A1, are substantially symmetrical to the firstreference plane P1 (see FIGS. 12 and 22). Additionally, by arranging therotation preventer in the first reference plane P1, to which the thrustacting planes P4 and P5 are symmetrical, rotation of the first lensframe 30 is prevented at a balanced neutral position relative to the twoactuators, so that the difference in thrust force between the twoactuators that is caused due to the difference in driving directiontherebetween and variations of the gap between each permanent magnet 81and 82 and the associated Hall sensor 85 or 86 in the two actuators canbe suppressed. However, the rotation preventer for the first lens frame30 can also be arranged at a position other than in the first referenceplane P1. Modified embodiments having such an arrangement are shown inFIGS. 38 through 43 as a tenth embodiment of the rotation preventer andin FIGS. 44 through 49 as an eleventh embodiment of the rotationpreventer.

In the tenth embodiment of the rotation preventer shown in FIGS. 38through 43, the rotation preventer for the first lens frame 30 ispositioned in the second reference plane P2 that is orthogonal to thefirst reference plane P1 under the condition that the arrangement of thetwo actuators are identical to that of the first embodiment of therotation preventer (see FIGS. 12, 13, 22 and 23). The base plate 60 ofthe sensor holder 34 is provided downward from the pivot recess 67 witha rotation prevention hole (projection insertion hole) 868. Similar tothe rotation prevention hole 68 of the first embodiment of the rotationpreventer, the rotation prevention hole 868 is an elongated hole whichis formed such that the length of the rotation prevention hole 868,which corresponds to the distance along a central line which connects apair of end portions 868 b of the rotation prevention hole 868, isgreater than the width of the rotation prevention hole 868, which isdefined by the distance between a pair of facing surfaces (holdingportions) 868 a of the rotation prevention hole 868, and the rotationprevention hole 868 is elongated in a radial direction, from anextension line of the first optical axis O1, on the third referenceplane P3; however, the elongated direction of the rotation preventionhole 868 and the formation position thereof are different from those ofthe rotation prevention hole 68. As can be seen from FIGS. 40 and 41,the rotation prevention hole 868 is positioned at the boundary betweenthe third quadrant V3 and the fourth quadrant V4 so that the pair offacing surfaces 868 a, which are parallel to the second reference planeP2, are substantially symmetrically arranged on the opposite sides ofthe second reference plane P2.

A pivot guide 839 is positioned downward from the pivot projection 44and is supported by the pivot arm 41 c of the first lens frame 30. Thepivot guide 839 is provided with a base 839 a which is embedded in thepivot arm 41 c, a guide projection (as an element of the rotationpreventer) 839 b, having a spherical barrel shape which is inserted intothe rotation prevention hole 868, and a large-diameter flange 839 cwhich is positioned between the base 839 a and the guide projection 839b to define the amount of projection of the guide projection 839 b. Inthe image-stabilizing initial state of the first lens frame 30 shown inFIGS. 38 through 43, the spherical guide projection 839 b comes incontact (point contact) with the pair of facing surfaces 868 a of therotation prevention hole 868 with a spherical center B3 positioned inthe third reference plane P3. In addition, the guide projection 839 bwhich is held between the pair of facing surfaces 868 a is slidablealong the pair of facing surfaces 868 a in a first plane that isparallel to the second reference plane P2 (see FIG. 42), and is slidablein the forward/rearward direction of the first optical axis O1 andswingable about the spherical center B3 as a swinging center (fulcrum)within a second plane (a plane that is parallel to the first referenceplane P1) orthogonal to the first plane and parallel to the firstoptical axis O1, while the guide projection 839 b which is held betweenthe pair of facing surfaces 868 a is prevented from moving in adirection of the width between the pair of facing surfaces 868 a (seeFIG. 43). Accordingly, the pivot guide 839 and the rotation preventionhole 868 prevent rotation of the first lens frame 30 about the opticalaxis of the first lens element L1 while allowing the first lens frame 30to perform the spherical swinging operation about the spherical-swingingcenter A1.

The tenth embodiment of the rotation preventer, which is configured ofthe pivot guide 839 and the rotation preventer 868, is asymmetricallyarranged with respect to the two actuators, and accordingly, there is apossibility of a difference in dynamic characteristic occurringdepending on the driving direction of the first lens frame 30. However,as for the accuracy of the spherical swinging operation of the firstlens frame 30 and the suppression of variations of the gap between eachpermanent magnet 81 and 82 and the associated Hall sensor 85 or 86,performance equivalent to that in the case where the rotation preventeris installed in the first reference plane P1 can be obtained.

In each of the above described embodiments (the first through tenthembodiments), the two actuators (i.e., the voice coil motors configuredof the permanent magnet 81 and the coil 83 and the voice coil motorsconfigured of the permanent magnet 82 and the coil 84) for driving ofthe first lens frame 30 to reduce image shake are arranged so that theintersecting angle D3 between the thrust acting plane P4 and the thrustacting plane P5 is approximately 60 degrees (see FIGS. 12, 22 and 40).Whereas, in the eleventh embodiment shown in FIGS. 44 through 49, athrust acting plane P14 and a thrust acting plane P15 are symmetrical tothe first reference plane P1 and intersect each other at angles ofapproximately ±45 degrees with respect to the first reference plane P1,as a plane of symmetry; namely, intersecting angle D4 between the thrustacting planes P14 and P15 is approximately 90 degrees (see FIG. 46). Thethrust acting plane P14 includes the spherical-swinging center A1 and athrust axis E11 (see FIG. 46) of the first actuator (a permanent magnet181 and an associated coil (not shown) which faces the permanent magnet181) and is parallel to (includes) the first optical axis O1. The thrustacting plane P15 includes the spherical-swinging center A1 and a thrustaxis E12 (see FIG. 46) of the second actuator (a permanent magnet 182and an associated coil (not shown) which faces the permanent magnet 182)and is parallel to (includes) the first optical axis O1. In accordancewith the arrangement of the thrust acting planes P14 and P15, a pair ofmagnet holding portions 142 and 143 of the first lens frame 30 (whichcorrespond to the above illustrated pair of magnet holding portion 42and 43) are configured to be spaced further apart from each other in theupward/downward direction of the imaging unit 10 than the pair of magnetholding portion 42 and 43 of the first lens frame 30 in each of theprevious embodiments; and a pair of sensor support projections 161 and162 of the sensor holder 34 (which correspond to the above illustratedpair of sensor support projections 61 and 62) are configured to bespaced further apart from each other in the upward/downward direction ofthe imaging unit 10 than the pair of sensor support projections 61 and62 of the sensor holder 34 in each of the previous embodiments.

As the thrust acting planes of the two actuators are positioned closerto the first reference plane P1 (i.e., as the intersecting angle betweenthe thrust acting planed becomes smaller), the configuration of the twoactuators becomes more advantageous for miniaturization of the imagingunit 10 in the upward/downward direction. However, making theintersecting angle between the thrust acting planes excessively smallmakes it difficult to perform a stable image-stabilizing control of thefirst lens frame 30 with high precision. The structure shown in FIGS. 12and 40 is such that the intersecting angle D3 between the thrust actingplane P4 and the thrust acting plane P5 is set at approximately 60degrees to reduce the size of the first lens-group unit 12 in theupward/downward direction and is within a range that does not impair thestability and accuracy of image-stabilizing control. Whereas, thestructure of the eleventh embodiment that is shown in FIG. 46 isadvantageous for ensuring the stability and accuracy ofimage-stabilizing control, although miniaturization of the imaging unit10 in the upward/downward direction is somewhat limited due to theaforementioned setting of the intersecting angle D4 between the thrustacting planes P14 and P15 at approximately 90 degrees.

The eleventh embodiment that is incorporated in the support structurefor the first lens element L1 shown in FIGS. 44 through 49 is suitablefor the condition in which the intersecting angle D4 between the thrustacting planes P14 and P15 is set at approximately 90 degrees. In otherwords, the rotation preventer for the first lens frame 30 is provided tolie in the thrust acting plane P15. The base plate 60 of the sensorholder 34 is provided with a rotation prevention hole (projectioninsertion portion) 968, at a position decentered downward and leftwardfrom the pivot recess 67. Similar to the rotation prevention hole 68 ofthe first embodiment, the rotation prevention hole 968 is an elongatedhole which is formed such that the length of the rotation preventionhole 968, which corresponds to the distance along a central line whichconnects a pair of end portions 968 b of the rotation prevention hole968, is greater than the width of the rotation prevention hole 968,which is defined by the distance between a pair of facing surfaces(holding portions) 968 a of the rotation prevention hole 968, and therotation prevention hole 968 is elongated in a radial direction of animaginary extension line of the first optical axis O1 in the thirdreference plane P3; however, the elongated direction of the rotationprevention hole 968 and the formation position thereof are differentfrom those of the rotation prevention hole 68. As can be seen from FIGS.46 and 47, the rotation prevention hole 968 is positioned in the thirdquadrant V3 so that the pair of facing surfaces 968 a, which areparallel to the thrust acting plane P15, are substantially symmetricallyarranged on the opposite sides of the thrust acting plane P15.

A pivot guide 939 is supported by the pivot arm 41 c of the first lensframe 30 at a position decentered downward and leftward from the pivotprojection 44. The pivot guide 939 is provided with a base 939 a whichis embedded in the pivot arm 41 c, a guide projection (as an element ofthe rotation preventer) 939 b, having a spherical barrel shape which isinserted into the rotation prevention hole 968, and a large-diameterflange 939 c which is positioned between the base 939 a and the guideprojection 939 b to define the amount of projection of the guideprojection 939 b. In the image-stabilizing initial state of the firstlens frame 30 shown in FIGS. 44 through 49, the spherical guideprojection 939 b comes in contact (point contact) with the pair offacing surfaces 968 a of the rotation prevention hole 968 with aspherical center B4 positioned in the third reference plane P3. Inaddition, the guide projection 939 b which is held between the pair offacing surfaces 968 a is slidable along the pair of facing surfaces 968a in a first plane that is parallel to the thrust acting plane P15 (seeFIG. 48), and is slidable in the forward/rearward direction of the firstoptical axis O1 and swingable about the spherical center B4 as aswinging center (fulcrum) in a second plane (a plane parallel to thethrust acting plane P14) orthogonal to the first plane and parallel tothe first optical axis O1, while the guide projection 939 b which isheld between the pair of facing surfaces 868 a is prevented from movingin a direction of the width between the pair of facing surfaces 968 a(see FIG. 49). Accordingly, the pivot guide 939 and the rotationprevention hole 968 prevents rotation of the first lens frame 30 aboutthe optical axis of the first lens element L1 while allowing the firstlens frame 30 to perform the spherical swinging operation about thespherical-swinging center A1. Note that the pivot guide 939 and therotation prevention hole 968 can be provided to lie in the thrust actingplane P14 instead of the thrust acting plane P15. Arranging the rotationpreventer in the thrust acting plane P15 (or the thrust acting planeP14) in such a manner when the thrust acting planes P14 and P15 of thetwo actuators are orthogonal to each other makes it possible to achieveexcellent accuracy and stability in the rotation limit control when thefirst lens frame 30 performs the spherical swinging operation.

In contrast, in the configuration as shown in in FIG. 12 or 40 in whichthe thrust acting planes P4 and P5 of the two actuators arenon-orthogonal to each other, if the rotation preventer is arranged ineither the thrust acting plane P4 or P5, this arrangement is suitablefor one of the two actuators, the thrust axis of which lies in thethrust acting plane P4 or P5 in which the rotation preventer isarranged, but is disadvantageous for the other actuator. For instance,if the rotation preventer is arranged in the thrust acting plane P4 inthe configuration shown in in FIG. 12 or 40, this arrangement issuitable for the actuator (the permanent magnet 81 and the coil 83), thethrust axis E1 of which lies in the thrust acting plane P4, butundesirable for the other actuator (the permanent magnet 82 and the coil84) because such an arrangement causes a difference in thrust due to thedifference in driving direction and causes variations in the gap betweenthe permanent magnet 82 and the Hall sensor 86. In the case where thethrust acting planes P4 and P5 of the two actuators are non-orthogonalto each other, it is desirable configure the support structure for thefirst lens element L1 so that the rotation preventer is arranged in aplane (the first reference plane P1) to which the thrust acting planesP4 and P5 are symmetrically arranged, or so that the rotation preventeris arranged in a plane (the second reference plane P2) orthogonal to aplane (the first reference plane P1) to which the thrust acting planesP4 and P5 are symmetrically arranged like the arrangement shown in FIG.40.

In the case of the rotation preventer in which the intersecting anglebetween the thrust acting planes (P14 and P15) of the two actuators isapproximately 90 degrees, as with the eleventh embodiment, the rotationpreventer can be provided in the first reference plane P1 or the secondreference plane P2.

Although the tenth embodiment of the rotation preventer is provided withthe pivot guide 839, which makes the guide projection 839 b contact thepair of facing surfaces 868 a of the rotation prevention hole 868, whilethe eleventh embodiment of the rotation preventer is provided with thepivot guide 939, which makes the guide projection 939 b contact the pairof facing surfaces 968 a of the rotation prevention hole 968, the pivotguide 839 and the pivot guide 939 can each be replaced by the guideshaft 539 of the seventh embodiment or the guide shaft 739 of the ninthembodiment as the rotation preventer disposed in the second referenceplane P2 or the thrust acting plane P14 or P15. In this case, it isadvisable for the rotation preventer be configured so that thespherical-swinging center A1 lies on an extension of the axis of theguide shaft, as described above. In addition, the shape of the guideprojection 839 b or 939 b of each pivot guide 839 and 939 is not limitedto a spherical barrel shape, as shown in the drawings, and can be, e.g.,completely spherical in shape as shown in FIGS. 24A and 24B, or each ofthe various cylindrical shapes shown in FIGS. 26A through 28C.

As illustrated above, in the imaging apparatus (the imaging unit 10)according to the present invention that is provided with one of theabove described (first through eleventh) embodiments, since the imagingapparatus is provided with the rotation preventer that prevents rotationof the first lens element L1 (the first lens frame 30) about the opticalaxis of the first lens element L1 while allowing the first lens frame 30to perform the spherical swinging operation about the spherical-swingingcenter A1, the two actuators (voice coil motors), the thrust actingplanes P4 (or P14) and P5 (or P15) of which intersect each other, makeit possible to allow the first lens frame 30 to perform the sphericalswinging operation with high precision and stability. The rotationpreventer is simple in structure, configured of a projection (a pivotguide or a guide shaft) and a projection insertion portion (rotationprevention hole) which are provided on the first lens frame 30 and asupport member therefor (a combination of the base member 31, the covermember 32 and the sensor holder 34), and the rotation preventer isarranged using the rear space 55, which is provided behind thereflection surface L11-c of the first prism L11, and accordingly, therotation preventer does not interfere with the miniaturization of theimaging unit 10.

Appropriate conditions for the arrangement of the rotation preventerwill be summarized hereinbelow. The arrangement of the rotationpreventer in the traveling direction of the first optical axis O1 (theforward/rearward direction of the imaging unit 10) is given as a firstcondition. In regard to the first condition, it is desirable to arrangethe rotation preventer in a plane (the third reference plane P3) whichpasses through the spherical-swinging center A1 and which is orthogonalto the first optical axis O1 (the first through seventh, tenth andeleventh embodiments), wherein the rotation preventer can be arranged ina plane shifted to some degree from this plane (the third referenceplane P3) in the direction of the first optical axis O1 (the eighth andninth embodiments). In the case where the rotation preventer is arrangedin such a shifted manner, arranging the rotation preventer behind thethird reference plane P3 may cause an increase in size of the imagingunit 10 in the forward/rearward direction, so that an arrangement isdesirable in which the rotation preventer is positioned in a planeshifted forward from the third reference plane P3, as shown in each ofthe eighth and ninth embodiments of the rotation preventers. Regardlessof whether the rotation preventer is arranged in a plane shifted or notshifted from the third reference plane P3, when a long projection like aguide shaft which is elongated in the axial direction thereof is used asan element of the rotation preventer, it is advisable for thespherical-swinging center A1 be positioned on an extension of the axisof such a guide shaft.

The arrangement of the rotation preventer in a plane orthogonal to thefirst optical axis O1 (in the upward/downward direction and theleftward/rightward direction of the imaging unit 10) is given as asecond condition. In regard to the second condition, it is desirable, interms of balance, to arrange the rotation preventer in a plane (thefirst reference plane P1), to which the thrust acting planes P4 (P14)and P5 (P15) of the two actuators are symmetrical (the first throughninth embodiments), and the present invention is satisfied even when therotation preventer is arranged in a plane (the second reference planeP2) orthogonal to the aforementioned plane (the first reference planeP1), to which the thrust acting planes P4 (P14) and P5 (P15) of the twoactuators are symmetrical (the tenth embodiment). Additionally, underthe condition that the two thrust acting planes P14 and P15 of the twoactuators are orthogonal to each other, the arrangement of the rotationpreventer in one of the two thrust acting planes P14 and P15 is alsodesirable (the eleventh embodiment).

If the rotation preventer is arranged under conditions far outside thefirst condition and/or the second condition, the disadvantages of adifference in thrust due to the difference in driving direction,variations in the gap between one permanent magnet (e.g., the permanentmagnet 82) and the associated Hall sensor (e.g., the Hall sensor 86), ordeterioration of the position sensitivity of the first lens frame 30,may occur when the first lens frame 30 is made to perform the sphericalswinging operation.

Although the present invention has been described based on the aboveillustrated embodiments, the present invention is not limited solelythereto; various modifications to the above illustrated embodiment arepossible without departing from the scope of the invention. Forinstance, although the imaging optical system of the above describedimaging apparatus uses a prism as a reflector element which bends anoptical path, the prism can be replaced by a mirror, or the like, as areflector element. Additionally, the present invention can also beapplied to a type of imaging apparatus which has an L-shaped opticalpath without including a reflector element corresponding to the secondprism L12 in the imaging optical system. Alternatively, the presentinvention can be applied to an imaging apparatus which contains abending optical system including one or more additional reflectorelements in addition to the first prism L11 and the second prism L12. Inany case, the bending angle (reflecting angle) of an optical axis by areflector element of the bending optical system can be any angle otherthan 90 degrees.

As described above, various modification can be made to the front lenselement (the first lens element L1) that is positioned on the objectside of the reflector element (which corresponds to the first prism L11in the above illustrated embodiments) to perform an image-stabilizingoperation. For instance, a plurality of front lens elements can beprovided instead of a single lens element.

The first lens element L1 in the above illustrated embodiments has aD-cut shape that is formed with a portion of the outer edge of the firstlens element L1 cut out, which contributes to miniaturization of thefirst lens-group unit 12 in a direction along the second optical axisO2. However, the front elevational shape of the front lens element inthe present invention is not limited to that of a D-cut lens element;the present invention is also applicable to an imaging apparatus whichincludes a front lens element having a shape (e.g., circular shape)different in front elevational view from a D-cut lens.

In the above illustrated embodiments, a combination of the base member31, the cover member 32 and the sensor holder 34 is used as a supportmember which supports the first lens frame 30 in a manner to allow thefirst lens frame 30 to perform the spherical swinging operation. Thisstructure makes it possible to achieve an excellent effect in assemblingworkability; however, a support member with which the base member 31,the sensor holder 34 or the like is integrally formed can also be used.Unlike the above illustrated embodiment of the imaging unit 10, it ispossible for the housing 13 (which holds the imaging sensor 14, thesecond prism L12 and other members) and the base member 31 (which holdsthe first prism L11) to be integrally formed to serve as an integratedsupport member and for the first lens frame 30 to be supported by thisintegrated support member.

The rotation preventer that prevents rotation of the first lens frame 30can adopt a different configuration from the configurations of the aboveillustrated embodiments, as long as the rotation preventer preventsrotation of the first lens frame 30 by engagement between a projectionand a projection insertion hole. As an example, in each of the aboveillustrated embodiments, the rotation prevention hole (68, 668, 868 or968) is an elongated hole which is formed so that the distance betweenthe pair of end portions (68 b, 668 b, 868 b or 968 b) (i.e., the lengthof the rotation prevention hole (68, 668, 868 or 968)) is greater thanthe distance between the pair of facing surfaces (68 a, 668 a, 868 a or968 a), which defines the width of the rotation prevention hole (68,668, 868 or 968). The reason why the rotation preventer uses anelongated hole is to allow the guide projection (39 b, 39 d, 39 e, 39 f,39 g, 39 h, 639 b, 839 b or 939 b) to slide along the pair of facingsurfaces (68 a, 668 a, 868 a or 968 a) when the first lens frame 30performs the spherical swinging operation. However, unlike the aboveillustrated embodiments, in the case of using a wide-profile guideprojection wherein the size thereof in the widthwise direction, in whichthe guide projection is held between the pair of facing surfaces of therotation prevention hole, is greater than that in the sliding directionrelative to the rotation prevention hole, it is possible to also use anon-elongated type rotation prevention hole wherein the distance betweenthe pair of facing surfaces (68 a, 668 a, 868 a or 968 a) is equal to orgreater than the distance between the pair of end portions (68 b, 668 b,868 b or 968 b).

In addition, although the pair of end portions (68 b, 668 b, 868 b or968 b) of the rotation prevention hole (68, 668, 868 or 968) are bothclosed in each of the above illustrated embodiments, a projectioninsertion portion having a shape like the rotation prevention hole 568or 768, in which one end portion or both end portions of the rotationprevention hole are not closed can also be used. In other words, aprojection insertion portion satisfies the requirements of the presentinvention as an element of the rotation preventer as long at least arotation preventing portion, such as the pair of facing surfaces 68 a,668 a, 868 a or 968 a or the pair of facing protrusions 568 a or 768 a,is included.

Although the first lens frame 30, which is a movable member, is providedwith a projection such as a pivot guide or a guide shaft while thesensor holder 34, which is fixed to the body of the imaging unit 10, isprovided with a rotation prevention hole which constitutes a rotationinsertion portion in each of the above illustrated embodiments, theprojection insertion portion and the projection can be provided on themovable frame and the fixed support member, respectively.

In each of the above illustrated embodiments, moving-magnet type voicecoil motors in which the permanent magnets 81 (181) and 82 (182) areheld by the movable first lens frame 30, and in which the coils 83 and84 are held by the stationary cover member 32, are used as actuatorswhich make the first lens frame 30 perform the spherical swingingoperation. Unlike the above illustrated embodiments, moving-coil typevoice coil motors, in which the coils are held on the movable first lensframe 30 and in which the permanent magnets are held on a support member(the base member 31, the cover member 32, the sensor holder 34, or thelike), which supports the first lens frame 30 in a manner to allow thefirst lens frame 30 to perform the spherical swinging operation, canalso be adopted. In this case, Hall sensors which detect the position ofthe first lens frame 30 can be held on the movable first lens frame 30.

The present invention does not limit the driver which makes the firstlens frame 30 perform the spherical swinging operation; actuators, otherthan voice coil motors, can also be used as long as satisfyingconditions that they are compatible with high-speed image-stabilizingdriving.

Obvious changes may be made in the specific embodiments of the presentinvention described herein, such modifications being within the spiritand scope of the invention claimed. It is indicated that all mattercontained herein is illustrative and does not limit the scope of thepresent invention.

What is claimed is:
 1. An imaging apparatus comprising: a front lensgroup which constitutes part of an imaging optical system of saidimaging apparatus and includes at least one front lens element and areflector, in that order from an object side, wherein said reflectorincludes a reflection surface which reflects light rays, exiting fromsaid front lens element, toward a different direction, and wherein saidimaging apparatus performs an image-stabilizing operation by drivingsaid front lens element in response to vibrations applied to saidimaging optical system in order to reduce image shake on said imageplane; at least one rear lens group which constitutes another part ofsaid imaging optical system and is positioned closer to an image planethan said front lens group; a movable frame which holds said front lenselement; a reflector support which supports at least said reflector andis immovable relative to an optical axis of said front lens element in areference state in which said imaging apparatus does not drive saidfront lens element when said image-stabilizing operation is notperformed; a movable-frame support which supports said movable frame ina manner to allow said movable frame to spherically swing along animaginary spherical surface about a spherical-swinging center which ispositioned on an extension of said optical axis, of said front lenselement, extending behind an underside of said reflection surface ofsaid reflector; and a rotation preventer which prevents rotation of saidmovable frame about said optical axis of said front lens elementrelative to said reflector support in said reference state and a statewhere said movable frame spherically swings about saidspherical-swinging center, while allowing said movable frame tospherically swing about said spherical-swinging center relative to saidreflector support, said rotation preventer including a projection and aprojection insertion portion which are provided on one and the other ofsaid movable frame and said reflector support reflector and engaged witheach other.
 2. The imaging apparatus according to claim 1, wherein saidprojection is slidable relative to said projection insertion portionalong a first plane which includes said optical axis of said front lenselement in said reference state, and wherein, with respect to movementof said projection within a second plane which is orthogonal to saidfirst plane and parallel to said optical axis of said front lens elementin said reference state, said projection is swingable relative to saidprojection insertion portion about a point of support which lies in saidsecond plane and movable relative to said projection insertion portionin a direction along said optical axis of said front lens element insaid reference state, and is prevented from moving relative to saidprojection insertion portion in a direction orthogonal to said opticalaxis of said front lens element in said reference state.
 3. The imagingapparatus according to claim 2, wherein said first plane includes saidoptical axis of said front lens element in said reference state and anoptical axis of light rays reflected by said reflector.
 4. The imagingapparatus according to claim 2, wherein said projection insertionportion comprises a pair of holding portions which face each other, oneither sides of said first plane, and hold said projection in saidsecond plane.
 5. The imaging apparatus according to claim 4, whereinsaid pair of holding portions comprise a pair of facing surfaces whichare parallel to said first plane, and wherein said projection comprisesa nonplanar contacting surface which is in sliding contact with saidpair of facing surfaces.
 6. The imaging apparatus according to claim 5,wherein said projection insertion portion comprises an elongated holewhich is formed such that a distance between a pair of end portions ofsaid elongated hole is greater than a distance between said pair offacing surfaces, and wherein said spherical-swinging center ispositioned on an extension of said elongated hole in the lengthwisedirection thereof.
 7. The imaging apparatus according to claim 4,wherein said projection comprises a guide shaft, an axis of whichextending along said first plane, and wherein said pair of holdingportions comprises a pair of facing protrusions which hold a portion ofsaid guide shaft in said axial direction thereof.
 8. The imagingapparatus according to claim 7, wherein said spherical-swinging centeris positioned on an extension of said axis of said guide shaft.
 9. Theimaging apparatus according to claim 1, wherein said projection and saidprojection insertion portion come in contact with each other in a planewhich passes through said spherical-swinging center and is orthogonal tosaid optical axis of said front lens element in said reference state.10. The imaging apparatus according to claim 1, comprising two actuatorswhich make said movable frame spherically swing about saidspherical-swinging center, wherein a first thrust acting plane, whichpasses through a center of an outer profile of one of said two actuatorsand includes a thrust acting direction of said one actuator, and asecond thrust acting plane, which passes through a center of an outerprofile of the other of said two actuators and includes a thrust actingdirection of said other actuator, are each parallel to said optical axisof said front lens element in said reference state, intersect each otherat said spherical-swinging center and are plane-symmetrical with respectto a plane of symmetry which passes through a point of said intersectionof said first thrust acting plane and said second thrust acting planeand is parallel to said optical axis of said front lens element in saidreference state, and wherein said projection and said projectioninsertion portion are positioned in said plane of symmetry, to whichsaid first thrust acting plane and said second thrust acting plane areplane-symmetrical.
 11. The imaging apparatus according to claim 10,wherein said first thrust acting plane and said second first thrustacting plane are orthogonal to each other.
 12. The imaging apparatusaccording to claim 1, comprising two actuators which make said movableframe spherically swing about said spherical-swinging center, wherein afirst thrust acting plane, which passes through a center of an outerprofile of one of said two actuators and includes a thrust actingdirection of said one actuator, and a second thrust acting plane, whichpasses through a center of an outer profile of the other of said twoactuators and includes a thrust acting direction of said other actuator,are each parallel to said optical axis of said front lens element insaid reference state, intersect each other at said spherical-swingingcenter and are plane-symmetrical with respect to a plane of symmetrywhich passes through a point of said intersection of said first thrustacting plane and said second thrust acting plane and is parallel to saidoptical axis of said front lens element in said reference state, andwherein said projection and said projection insertion portion arepositioned in a plane that is orthogonal to said plane of symmetry, towhich said first thrust acting plane and said second thrust acting planeare plane-symmetrical.
 13. The imaging apparatus according to claim 12,wherein said first thrust acting plane and said second first thrustacting plane are orthogonal to each other.
 14. The imaging apparatusaccording to claim 1, comprising two actuators which make said movableframe spherically swing about said spherical-swinging center, wherein afirst thrust acting plane, which passes through a center of an outerprofile of one of said two actuators and includes a thrust actingdirection of said one actuator, and a second thrust acting plane, whichpasses through a center of an outer profile of the other of said twoactuators and includes a thrust acting direction of said other actuator,are each parallel to said optical axis of said front lens element insaid reference state, intersect each other at said spherical-swingingcenter and are plane-symmetrical with respect to a plane of symmetrywhich passes through a point of said intersection of said first thrustacting plane and said second thrust acting plane and is parallel to saidoptical axis of said front lens element in said reference state, andwherein said projection and said projection insertion portion arepositioned in one of said first thrust acting plane and said secondthrust acting plane.
 15. The imaging apparatus according to claim 14,wherein said first thrust acting plane and said second first thrustacting plane are orthogonal to each other.
 16. The imaging apparatusaccording to claim 1, wherein said movable frame comprises saidprojection and said reflector support comprises said projectioninsertion portion.